Class.java

/*
 * Copyright (c) 1994, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.lang;

import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectStreamField;
import java.io.Serializable;
import java.lang.annotation.Annotation;
import java.lang.module.ModuleReader;
import java.lang.ref.SoftReference;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.AnnotatedType;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Executable;
import java.lang.reflect.Field;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.GenericDeclaration;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Proxy;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.ProtectionDomain;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.StringJoiner;
import jdk.internal.HotSpotIntrinsicCandidate;
import jdk.internal.loader.BootLoader;
import jdk.internal.loader.BuiltinClassLoader;
import jdk.internal.misc.Unsafe;
import jdk.internal.module.Resources;
import jdk.internal.reflect.CallerSensitive;
import jdk.internal.reflect.ConstantPool;
import jdk.internal.reflect.Reflection;
import jdk.internal.reflect.ReflectionFactory;
import jdk.internal.vm.annotation.ForceInline;
import sun.reflect.annotation.AnnotationParser;
import sun.reflect.annotation.AnnotationSupport;
import sun.reflect.annotation.AnnotationType;
import sun.reflect.annotation.TypeAnnotationParser;
import sun.reflect.generics.factory.CoreReflectionFactory;
import sun.reflect.generics.factory.GenericsFactory;
import sun.reflect.generics.repository.ClassRepository;
import sun.reflect.generics.repository.ConstructorRepository;
import sun.reflect.generics.repository.MethodRepository;
import sun.reflect.generics.scope.ClassScope;
import sun.reflect.misc.ReflectUtil;
import sun.security.util.SecurityConstants;

/**
 * Instances of the class {@code Class} represent classes and interfaces
 * in a running Java application. An enum type is a kind of class and an
 * annotation type is a kind of interface. Every array also
 * belongs to a class that is reflected as a {@code Class} object
 * that is shared by all arrays with the same element type and number
 * of dimensions.  The primitive Java types ({@code boolean},
 * {@code byte}, {@code char}, {@code short},
 * {@code int}, {@code long}, {@code float}, and
 * {@code double}), and the keyword {@code void} are also
 * represented as {@code Class} objects.
 *
 * <p> {@code Class} has no public constructor. Instead a {@code Class}
 * object is constructed automatically by the Java Virtual Machine
 * when a class loader invokes one of the
 * {@link ClassLoader#defineClass(String, byte[], int, int) defineClass} methods
 * and passes the bytes of a {@code class} file.
 *
 * <p> The methods of class {@code Class} expose many characteristics of a
 * class or interface. Most characteristics are derived from the {@code class}
 * file that the class loader passed to the Java Virtual Machine. A few
 * characteristics are determined by the class loading environment at run time,
 * such as the module returned by {@link #getModule() getModule()}.
 *
 * <p> Some methods of class {@code Class} expose whether the declaration of
 * a class or interface in Java source code was <em>enclosed</em> within
 * another declaration. Other methods describe how a class or interface
 * is situated in a <em>nest</em>. A <a id="nest">nest</a> is a set of
 * classes and interfaces, in the same run-time package, that
 * allow mutual access to their {@code private} members.
 * The classes and interfaces are known as <em>nestmates</em>.
 * One nestmate acts as the
 * <em>nest host</em>, and enumerates the other nestmates which
 * belong to the nest; each of them in turn records it as the nest host.
 * The classes and interfaces which belong to a nest, including its host, are
 * determined when
 * {@code class} files are generated, for example, a Java compiler
 * will typically record a top-level class as the host of a nest where the
 * other members are the classes and interfaces whose declarations are
 * enclosed within the top-level class declaration.
 *
 * <p> The following example uses a {@code Class} object to print the
 * class name of an object:
 *
 * <blockquote><pre>
 *     void printClassName(Object obj) {
 *         System.out.println("The class of " + obj +
 *                            " is " + obj.getClass().getName());
 *     }
 * </pre></blockquote>
 *
 * <p> It is also possible to get the {@code Class} object for a named
 * type (or for void) using a class literal.  See Section 15.8.2 of
 * <cite>The Java&trade; Language Specification</cite>.
 * For example:
 *
 * <blockquote>
 * {@code System.out.println("The name of class Foo is: "+Foo.class.getName());}
 * </blockquote>
 *
 * @param <T> the type of the class modeled by this {@code Class}
 *            object.  For example, the type of {@code String.class} is {@code
 *            Class<String>}.  Use {@code Class<?>} if the class being modeled is
 *            unknown.
 *
 * @author unascribed
 * @see java.lang.ClassLoader#defineClass(byte[], int, int)
 * @since 1.0
 */
// 反射元素-类/接口
public final class Class<T> implements Serializable, GenericDeclaration, Type, AnnotatedElement {
    /** use serialVersionUID from JDK 1.1 for interoperability */
    private static final long serialVersionUID = 3206093459760846163L;
    
    private static final int ANNOTATION = 0x00002000;
    private static final int ENUM = 0x00004000;
    private static final int SYNTHETIC = 0x00001000;
    
    /**
     * Class Class is special cased within the Serialization Stream Protocol.
     *
     * A Class instance is written initially into an ObjectOutputStream in the
     * following format:
     * <pre>
     *      {@code TC_CLASS} ClassDescriptor
     *      A ClassDescriptor is a special cased serialization of
     *      a {@code java.io.ObjectStreamClass} instance.
     * </pre>
     * A new handle is generated for the initial time the class descriptor
     * is written into the stream. Future references to the class descriptor
     * are written as references to the initial class descriptor instance.
     *
     * @see java.io.ObjectStreamClass
     */
    private static final ObjectStreamField[] serialPersistentFields = new ObjectStreamField[0];
    
    private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0];
    
    /**
     * Initialized in JVM not by private constructor
     * This field is filtered from reflection access, i.e. getDeclaredField will throw NoSuchFieldException
     */
    // 当前类关联的类加载器
    private final ClassLoader classLoader;
    
    // 数组的组件类型，int[]对应int，int[][]对应int[]，不是数组则为null
    private final Class<?> componentType;
    
    
    /** protection domain returned when the internal domain is null */
    private static ProtectionDomain allPermDomain;
    
    private static ReflectionFactory reflectionFactory;
    
    private transient volatile Constructor<T> cachedConstructor;
    
    private transient volatile Class<?> newInstanceCallerCache;
    
    private transient volatile SoftReference<ReflectionData<T>> reflectionData;
    
    // Incremented by the VM on each call to JVM TI RedefineClasses() that redefines this class or a superclass.
    private transient volatile int classRedefinedCount;
    
    // Generic info repository; lazily initialized
    private transient volatile ClassRepository genericInfo;
    
    private transient volatile T[] enumConstants;
    
    private transient volatile Map<String, T> enumConstantDirectory;
    
    // Annotations cache
    @SuppressWarnings("UnusedDeclaration")
    private transient volatile AnnotationData annotationData;
    
    @SuppressWarnings("UnusedDeclaration")
    private transient volatile AnnotationType annotationType;
    
    // cache the name to reduce the number of calls into the VM
    private transient String name;
    
    // set by VM
    private transient Module module;
    
    // cached package name
    private transient String packageName;
    
    /**
     * Backing store of user-defined values pertaining to this class.
     * Maintained by the ClassValue class.
     */
    transient ClassValue.ClassValueMap classValueMap;
    
    
    static {
        registerNatives();
    }
    
    
    
    /*▼ 构造器 ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Private constructor. Only the Java Virtual Machine creates Class objects.
     * This constructor is not used and prevents the default constructor being generated.
     */
    private Class(ClassLoader loader, Class<?> arrayComponentType) {
        // Initialize final field for classLoader.
        // The initialization value of non-null prevents future JIT optimizations from assuming this final field is null.
        classLoader = loader;
        componentType = arrayComponentType;
    }
    
    /*▲ 构造器 ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ 加载类 ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Returns the {@code Class} object associated with the class or
     * interface with the given string name.  Invoking this method is
     * equivalent to:
     *
     * <blockquote>
     * {@code Class.forName(className, true, currentLoader)}
     * </blockquote>
     *
     * where {@code currentLoader} denotes the defining class loader of
     * the current class.
     *
     * <p> For example, the following code fragment returns the
     * runtime {@code Class} descriptor for the class named
     * {@code java.lang.Thread}:
     *
     * <blockquote>
     * {@code Class t = Class.forName("java.lang.Thread")}
     * </blockquote>
     * <p>
     * A call to {@code forName("X")} causes the class named
     * {@code X} to be initialized.
     *
     * @param className the fully qualified name of the desired class.
     *
     * @return the {@code Class} object for the class with the
     * specified name.
     *
     * @throws LinkageError                if the linkage fails
     * @throws ExceptionInInitializerError if the initialization provoked
     *                                     by this method fails
     * @throws ClassNotFoundException      if the class cannot be located
     */
    // 根据类的全名加载类对象，而且加载类之后对类的静态元素进行初始化
    @CallerSensitive
    public static Class<?> forName(String className) throws ClassNotFoundException {
        Class<?> caller = Reflection.getCallerClass();
        return forName0(className, true, ClassLoader.getClassLoader(caller), caller);
    }
    
    /**
     * Returns the {@code Class} object associated with the class or
     * interface with the given string name, using the given class loader.
     * Given the fully qualified name for a class or interface (in the same
     * format returned by {@code getName}) this method attempts to
     * locate, load, and link the class or interface.  The specified class
     * loader is used to load the class or interface.  If the parameter
     * {@code loader} is null, the class is loaded through the bootstrap
     * class loader.  The class is initialized only if the
     * {@code initialize} parameter is {@code true} and if it has
     * not been initialized earlier.
     *
     * <p> If {@code name} denotes a primitive type or void, an attempt
     * will be made to locate a user-defined class in the unnamed package whose
     * name is {@code name}. Therefore, this method cannot be used to
     * obtain any of the {@code Class} objects representing primitive
     * types or void.
     *
     * <p> If {@code name} denotes an array class, the component type of
     * the array class is loaded but not initialized.
     *
     * <p> For example, in an instance method the expression:
     *
     * <blockquote>
     * {@code Class.forName("Foo")}
     * </blockquote>
     *
     * is equivalent to:
     *
     * <blockquote>
     * {@code Class.forName("Foo", true, this.getClass().getClassLoader())}
     * </blockquote>
     *
     * Note that this method throws errors related to loading, linking or
     * initializing as specified in Sections 12.2, 12.3 and 12.4 of <em>The
     * Java Language Specification</em>.
     * Note that this method does not check whether the requested class
     * is accessible to its caller.
     *
     * @param className  fully qualified name of the desired class
     * @param initialize if {@code true} the class will be initialized.
     *                   See Section 12.4 of <em>The Java Language Specification</em>.
     * @param loader     class loader from which the class must be loaded
     *
     * @return class object representing the desired class
     *
     * @throws LinkageError                if the linkage fails
     * @throws ExceptionInInitializerError if the initialization provoked
     *                                     by this method fails
     * @throws ClassNotFoundException      if the class cannot be located by
     *                                     the specified class loader
     * @throws SecurityException           if a security manager is present, and the {@code loader} is
     *                                     {@code null}, and the caller's class loader is not
     *                                     {@code null}, and the caller does not have the
     *                                     {@link RuntimePermission}{@code ("getClassLoader")}
     * @see java.lang.Class#forName(String)
     * @see java.lang.ClassLoader
     * @since 1.2
     */
    // 根据类的全名和指定的类加载器加载类对象，initialize参数指示是否在加载类之后对类中的静态元素进行初始化
    @CallerSensitive
    public static Class<?> forName(String className, boolean initialize, ClassLoader loader) throws ClassNotFoundException {
        Class<?> caller = null;
        
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            /*
             * Reflective call to get caller class is only needed if a security manager is present.
             * Avoid the overhead of making this call otherwise.
             */
            caller = Reflection.getCallerClass();
            if(loader == null) {
                ClassLoader ccl = ClassLoader.getClassLoader(caller);
                if(ccl != null) {
                    sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
                }
            }
        }
        
        return forName0(className, initialize, loader, caller);
    }
    
    /**
     * Returns the {@code Class} with the given <a href="ClassLoader.html#name">
     * binary name</a> in the given module.
     *
     * <p> This method attempts to locate, load, and link the class or interface.
     * It does not run the class initializer.  If the class is not found, this
     * method returns {@code null}. </p>
     *
     * <p> If the class loader of the given module defines other modules and
     * the given name is a class defined in a different module, this method
     * returns {@code null} after the class is loaded. </p>
     *
     * <p> This method does not check whether the requested class is
     * accessible to its caller. </p>
     *
     * @param module A module
     * @param name   The <a href="ClassLoader.html#name">binary name</a>
     *               of the class
     *
     * @return {@code Class} object of the given name defined in the given module;
     * {@code null} if not found.
     *
     * @throws NullPointerException if the given module or name is {@code null}
     * @throws LinkageError         if the linkage fails
     * @throws SecurityException    <ul>
     *                              <li> if the caller is not the specified module and
     *                              {@code RuntimePermission("getClassLoader")} permission is denied; or</li>
     *                              <li> access to the module content is denied. For example,
     *                              permission check will be performed when a class loader calls
     *                              {@link ModuleReader#open(String)} to read the bytes of a class file
     *                              in a module.</li>
     *                              </ul>
     * @apiNote This method returns {@code null} on failure rather than
     * throwing a {@link ClassNotFoundException}, as is done by
     * the {@link #forName(String, boolean, ClassLoader)} method.
     * The security check is a stack-based permission check if the caller
     * loads a class in another module.
     * @spec JPMS
     * @since 9
     */
    // 根据类的全名和所在的Module加载类对象(不会初始化)，如果该module下没有该类，返回null
    @CallerSensitive
    public static Class<?> forName(Module module, String name) {
        Objects.requireNonNull(module);
        Objects.requireNonNull(name);
    
        // 加载模块module的类加载器
        ClassLoader cl;
    
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            Class<?> caller = Reflection.getCallerClass();
            if(caller != null && caller.getModule() != module) {
                // if caller is null, Class.forName is the last java frame on the stack. java.base has all permissions
                sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
            }
            PrivilegedAction<ClassLoader> pa = module::getClassLoader;
            cl = AccessController.doPrivileged(pa);
        } else {
            cl = module.getClassLoader();
        }
    
        // 处理BootClassLoader情形
        if(cl == null) {
            // 通过bootstrap类加载器查找类是否已加载，如果找不到则返回null
            return BootLoader.loadClass(module, name);
        } else {
            // 根据给定的模块名与类的全名加载类
            return cl.loadClass(module, name);
        }
    }
    
    /*▲ 加载类 ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ 创建对象 ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Creates a new instance of the class represented by this {@code Class} object.
     * The class is instantiated as if by a {@code new} expression with an empty argument list.
     * The class is initialized if it has not already been initialized.
     *
     * @return a newly allocated instance of the class represented by this object.
     *
     * @throws IllegalAccessException      if the class or its nullary
     *                                     constructor is not accessible.
     * @throws InstantiationException      if this {@code Class} represents an abstract class,
     *                                     an interface, an array class, a primitive type, or void;
     *                                     or if the class has no nullary constructor;
     *                                     or if the instantiation fails for some other reason.
     * @throws ExceptionInInitializerError if the initialization
     *                                     provoked by this method fails.
     * @throws SecurityException           If a security manager, <i>s</i>, is present and
     *                                     the caller's class loader is not the same as or an
     *                                     ancestor of the class loader for the current class and
     *                                     invocation of {@link SecurityManager#checkPackageAccess
     *                                     s.checkPackageAccess()} denies access to the package
     *                                     of this class.
     * @deprecated This method propagates any exception thrown by the nullary constructor, including a checked exception.
     *             Use of this method effectively bypasses the compile-time exception checking that would otherwise be performed by the compiler.
     *             The {@link java.lang.reflect.Constructor#newInstance(java.lang.Object...) Constructor.newInstance} method avoids this problem
     *             by wrapping any exception thrown by the constructor in a (checked) {@link java.lang.reflect.InvocationTargetException}.
     *
     * <p>The call
     *
     * <pre>{@code
     * clazz.newInstance()
     * }</pre>
     *
     * can be replaced by
     *
     * <pre>{@code
     * clazz.getDeclaredConstructor().newInstance()
     * }</pre>
     *
     * The latter sequence of calls is inferred to be able to throw the additional exception types {@link InvocationTargetException} and {@link NoSuchMethodException}.
     * Both of these exception types are subclasses of {@link ReflectiveOperationException}.
     */
    // 创建当前类的对象（该方法已过时，不再建议使用）
    @CallerSensitive
    @Deprecated(since = "9")
    public T newInstance() throws InstantiationException, IllegalAccessException {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), false);
        }
        
        /* NOTE: the following code may not be strictly correct under the current Java memory model. */
        
        // Constructor lookup
        if(cachedConstructor == null) {
            if(this == Class.class) {
                throw new IllegalAccessException("Can not call newInstance() on the Class for java.lang.Class");
            }
            
            try {
                Class<?>[] empty = {};
    
                final Constructor<T> c = getReflectionFactory().copyConstructor(getConstructor0(empty, Member.DECLARED));
    
                /*
                 * Disable accessibility checks on the constructor since we have to do the security check here anyway
                 * (the stack depth is wrong for the Constructor's security check to work)
                 */
                AccessController.doPrivileged(new PrivilegedAction<>() {
                    public Void run() {
                        c.setAccessible(true);
                        return null;
                    }
                });
                cachedConstructor = c;
            } catch(NoSuchMethodException e) {
                throw (InstantiationException) new InstantiationException(getName()).initCause(e);
            }
        }
        
        Constructor<T> tmpConstructor = cachedConstructor;
        
        // Security check (same as in java.lang.reflect.Constructor)
        Class<?> caller = Reflection.getCallerClass();
        if(newInstanceCallerCache != caller) {
            int modifiers = tmpConstructor.getModifiers();
            Reflection.ensureMemberAccess(caller, this, this, modifiers);
            newInstanceCallerCache = caller;
        }
        
        // Run constructor
        try {
            return tmpConstructor.newInstance((Object[]) null);
        } catch(InvocationTargetException e) {
            Unsafe.getUnsafe().throwException(e.getTargetException());
            // Not reached
            return null;
        }
    }
    
    /*▲ 创建对象 ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ 获取类名 ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /* 参见ClassTest文件夹中com.kang.clazz.test02下的测试类 */
    
    /**
     * Returns the  name of the entity (class, interface, array class,
     * primitive type, or void) represented by this {@code Class} object,
     * as a {@code String}.
     *
     * <p> If this class object represents a reference type that is not an
     * array type then the binary name of the class is returned, as specified
     * by
     * <cite>The Java&trade; Language Specification</cite>.
     *
     * <p> If this class object represents a primitive type or void, then the
     * name returned is a {@code String} equal to the Java language
     * keyword corresponding to the primitive type or void.
     *
     * <p> If this class object represents a class of arrays, then the internal
     * form of the name consists of the name of the element type preceded by
     * one or more '{@code [}' characters representing the depth of the array
     * nesting.  The encoding of element type names is as follows:
     *
     * <blockquote><table class="striped">
     * <caption style="display:none">Element types and encodings</caption>
     * <thead>
     * <tr><th scope="col"> Element Type <th scope="col"> Encoding
     * </thead>
     * <tbody style="text-align:left">
     * <tr><th scope="row"> boolean      <td style="text-align:center"> Z
     * <tr><th scope="row"> byte         <td style="text-align:center"> B
     * <tr><th scope="row"> char         <td style="text-align:center"> C
     * <tr><th scope="row"> class or interface
     * <td style="text-align:center"> L<i>classname</i>;
     * <tr><th scope="row"> double       <td style="text-align:center"> D
     * <tr><th scope="row"> float        <td style="text-align:center"> F
     * <tr><th scope="row"> int          <td style="text-align:center"> I
     * <tr><th scope="row"> long         <td style="text-align:center"> J
     * <tr><th scope="row"> short        <td style="text-align:center"> S
     * </tbody>
     * </table></blockquote>
     *
     * <p> The class or interface name <i>classname</i> is the binary name of
     * the class specified above.
     *
     * <p> Examples:
     * <blockquote><pre>
     * String.class.getName()
     *     returns "java.lang.String"
     * byte.class.getName()
     *     returns "byte"
     * (new Object[3]).getClass().getName()
     *     returns "[Ljava.lang.Object;"
     * (new int[3][4][5][6][7][8][9]).getClass().getName()
     *     returns "[[[[[[[I"
     * </pre></blockquote>
     *
     * @return the name of the class or interface
     * represented by this object.
     */
    /*
     * 虚拟机中呈现的名称
     *
     * char                                 基本类型
     * [C                                   基本类型数组
     * com.kang.Outer                       引用类型
     * [Lcom.kang.Outer;                    引用类型数组
     * com.kang.Outer$Inner                 内部类
     * com.kang.Outer$1                     匿名类
     * com.kang.Outer$$Lambda$1/1989780873  Lambda表达式
     */
    public String getName() {
        String name = this.name;
        if(name == null) {
            this.name = name = getName0();
        }
        return name;
    }
    
    /**
     * Returns the canonical name of the underlying class as
     * defined by the Java Language Specification.  Returns null if
     * the underlying class does not have a canonical name (i.e., if
     * it is a local or anonymous class or an array whose component
     * type does not have a canonical name).
     *
     * @return the canonical name of the underlying class if it exists, and
     * {@code null} otherwise.
     *
     * @since 1.5
     */
    /*
     * 规范名称，尽量遵从书写习惯（匿名类为null）
     *
     * char                                 基本类型
     * char[]                               基本类型数组
     * com.kang.Outer                       引用类型
     * com.kang.Outer[]                     引用类型数组
     * com.kang.Outer.Inner                 内部类
     * null                                 匿名类
     * com.kang.Outer$$Lambda$1/1989780873  Lambda表达式
     */
    public String getCanonicalName() {
        ReflectionData<T> rd = reflectionData();
        String canonicalName = rd.canonicalName;
        if(canonicalName == null) {
            rd.canonicalName = canonicalName = getCanonicalName0();
        }
        return canonicalName == ReflectionData.NULL_SENTINEL ? null : canonicalName;
    }
    
    /**
     * Returns the simple name of the underlying class as given in the
     * source code. Returns an empty string if the underlying class is
     * anonymous.
     *
     * <p>The simple name of an array is the simple name of the
     * component type with "[]" appended.  In particular the simple
     * name of an array whose component type is anonymous is "[]".
     *
     * @return the simple name of the underlying class
     *
     * @since 1.5
     */
    /*
     * 简单名称，可以看做是不带包名和外部类名的规范名（匿名类没有）
     *
     * char                        基本类型
     * char[]                      基本类型数组
     * Outer                       引用类型
     * Outer[]                     引用类型数组
     * Inner                       内部类
     *                             匿名类
     * Outer$$Lambda$1/1989780873  Lambda表达式
     */
    public String getSimpleName() {
        ReflectionData<T> rd = reflectionData();
        String simpleName = rd.simpleName;
        if(simpleName == null) {
            rd.simpleName = simpleName = getSimpleName0();
        }
        return simpleName;
    }
    
    /**
     * Return an informative string for the name of this type.
     *
     * @return an informative string for the name of this type
     *
     * @since 1.8
     */
    /*
     * 类型名称
     *
     * char                                 基本类型
     * char[]                               基本类型数组
     * com.kang.Outer                       引用类型
     * com.kang.Outer[]                     引用类型数组
     * com.kang.Outer$Inner                 内部类
     * com.kang.Outer$1                     匿名类
     * com.kang.Outer$$Lambda$1/1989780873  Lambda表达式
     */
    public String getTypeName() {
        if(isArray()) {
            try {
                Class<?> cl = this;
                int dimensions = 0;
                do {
                    dimensions++;
                    cl = cl.getComponentType();
                } while(cl.isArray());
                StringBuilder sb = new StringBuilder();
                sb.append(cl.getName());
                for(int i = 0; i<dimensions; i++) {
                    sb.append("[]");
                }
                return sb.toString();
            } catch(Throwable e) { /*FALLTHRU*/ }
        }
        return getName();
    }
    
    /*▲ 获取类名 ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ isXXX ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Determines if the specified {@code Object} is assignment-compatible
     * with the object represented by this {@code Class}.  This method is
     * the dynamic equivalent of the Java language {@code instanceof}
     * operator. The method returns {@code true} if the specified
     * {@code Object} argument is non-null and can be cast to the
     * reference type represented by this {@code Class} object without
     * raising a {@code ClassCastException.} It returns {@code false}
     * otherwise.
     *
     * <p> Specifically, if this {@code Class} object represents a
     * declared class, this method returns {@code true} if the specified
     * {@code Object} argument is an instance of the represented class (or
     * of any of its subclasses); it returns {@code false} otherwise. If
     * this {@code Class} object represents an array class, this method
     * returns {@code true} if the specified {@code Object} argument
     * can be converted to an object of the array class by an identity
     * conversion or by a widening reference conversion; it returns
     * {@code false} otherwise. If this {@code Class} object
     * represents an interface, this method returns {@code true} if the
     * class or any superclass of the specified {@code Object} argument
     * implements this interface; it returns {@code false} otherwise. If
     * this {@code Class} object represents a primitive type, this method
     * returns {@code false}.
     *
     * @param obj the object to check
     *
     * @return true if {@code obj} is an instance of this class
     *
     * @since 1.1
     */
    /*
     * X.class.isInstance(obj) ==> 判断[对象]obj是否可以作为X类的实例
     * obj instanceof X 与上述调用作用一致
     * 关键字instanceof更简洁，isInstance()方法更灵活
     */
    @HotSpotIntrinsicCandidate
    public native boolean isInstance(Object obj);
    
    /**
     * Determines if the class or interface represented by this
     * {@code Class} object is either the same as, or is a superclass or
     * superinterface of, the class or interface represented by the specified
     * {@code Class} parameter. It returns {@code true} if so;
     * otherwise it returns {@code false}. If this {@code Class}
     * object represents a primitive type, this method returns
     * {@code true} if the specified {@code Class} parameter is
     * exactly this {@code Class} object; otherwise it returns
     * {@code false}.
     *
     * <p> Specifically, this method tests whether the type represented by the
     * specified {@code Class} parameter can be converted to the type
     * represented by this {@code Class} object via an identity conversion
     * or via a widening reference conversion. See <em>The Java Language
     * Specification</em>, sections 5.1.1 and 5.1.4 , for details.
     *
     * @param cls the {@code Class} object to be checked
     *
     * @return the {@code boolean} value indicating whether objects of the
     * type {@code cls} can be assigned to objects of this class
     *
     * @throws NullPointerException if the specified Class parameter is
     *                              null.
     * @since 1.1
     */
    /*
     * X.class.isAssignableFrom(cls) ==> 判断cls类型的对象是否为X类型的实例
     * 即判断X与cls所属的类/接口是否相同，或者X是cls的父类/父接口
     */
    @HotSpotIntrinsicCandidate
    public native boolean isAssignableFrom(Class<?> cls);
    
    /**
     * Determines if the specified {@code Class} object represents an
     * interface type.
     *
     * @return {@code true} if this object represents an interface;
     * {@code false} otherwise.
     */
    // X.class.isInterface() ==> 判断X是否为接口
    @HotSpotIntrinsicCandidate
    public native boolean isInterface();
    
    /**
     * Returns true if this {@code Class} object represents an annotation
     * type.  Note that if this method returns true, {@link #isInterface()}
     * would also return true, as all annotation types are also interfaces.
     *
     * @return {@code true} if this class object represents an annotation
     * type; {@code false} otherwise
     *
     * @since 1.5
     */
    // X.class.isAnnotation() ==> 判断X是否为注解类，如果成立，则X.class.isInterface()也返回true
    public boolean isAnnotation() {
        return (getModifiers() & ANNOTATION) != 0;
    }
    
    /**
     * Determines if the specified {@code Class} object represents a
     * primitive type.
     *
     * <p> There are nine predefined {@code Class} objects to represent
     * the eight primitive types and void.  These are created by the Java
     * Virtual Machine, and have the same names as the primitive types that
     * they represent, namely {@code boolean}, {@code byte},
     * {@code char}, {@code short}, {@code int},
     * {@code long}, {@code float}, and {@code double}.
     *
     * <p> These objects may only be accessed via the following public static
     * final variables, and are the only {@code Class} objects for which
     * this method returns {@code true}.
     *
     * @return true if and only if this class represents a primitive type
     *
     * @see java.lang.Boolean#TYPE
     * @see java.lang.Character#TYPE
     * @see java.lang.Byte#TYPE
     * @see java.lang.Short#TYPE
     * @see java.lang.Integer#TYPE
     * @see java.lang.Long#TYPE
     * @see java.lang.Float#TYPE
     * @see java.lang.Double#TYPE
     * @see java.lang.Void#TYPE
     * @since 1.1
     */
    // X.class.isPrimitive() ==> 判断X是否为基本类型，如int.class
    @HotSpotIntrinsicCandidate
    public native boolean isPrimitive();
    
    /**
     * Determines if this {@code Class} object represents an array class.
     *
     * @return {@code true} if this object represents an array class;
     * {@code false} otherwise.
     *
     * @since 1.1
     */
    // X.class.isArray() ==> 判断X是否为数组
    @HotSpotIntrinsicCandidate
    public native boolean isArray();
    
    /**
     * Returns true if and only if this class was declared as an enum in the
     * source code.
     *
     * @return true if and only if this class was declared as an enum in the
     * source code
     *
     * @since 1.5
     */
    // X.class.isEnum() ==> 判断X是否为枚举
    public boolean isEnum() {
        // An enum must both directly extend java.lang.Enum and have the ENUM bit set;
        // classes for specialized enum constants don't do the former.
        return (this.getModifiers() & ENUM) != 0 && this.getSuperclass() == java.lang.Enum.class;
    }
    
    /**
     * Returns {@code true} if and only if the underlying class is an anonymous class.
     *
     * @return {@code true} if and only if this class is an anonymous class.
     *
     * @since 1.5
     */
    // X.class.isAnonymousClass() ==> 判断X是否为匿名类
    public boolean isAnonymousClass() {
        return !isArray() && isLocalOrAnonymousClass() && getSimpleBinaryName0() == null;
    }
    
    /**
     * Returns {@code true} if and only if the underlying class
     * is a local class.
     *
     * @return {@code true} if and only if this class is a local class.
     *
     * @since 1.5
     */
    // X.class.isLocalClass() ==> 判断X是否为方法内部类
    public boolean isLocalClass() {
        return isLocalOrAnonymousClass() && (isArray() || getSimpleBinaryName0() != null);
    }
    
    /**
     * Returns {@code true} if and only if the underlying class
     * is a member class.
     *
     * @return {@code true} if and only if this class is a member class.
     *
     * @since 1.5
     */
    // X.class.isMemberClass() ==> 判断X是否为成员内部类
    public boolean isMemberClass() {
        return !isLocalOrAnonymousClass() && getDeclaringClass0() != null;
    }
    
    /**
     * Returns {@code true} if this class is a synthetic class;
     * returns {@code false} otherwise.
     *
     * @return {@code true} if and only if this class is a synthetic class as
     * defined by the Java Language Specification.
     *
     * @jls 13.1 The Form of a Binary
     * @since 1.5
     */
    // 合成类，一般是代理形式。如((Runnable) () -> {}).getClass().isSynthetic()为true
    public boolean isSynthetic() {
        return (getModifiers() & SYNTHETIC) != 0;
    }
    
    /**
     * {@inheritDoc}
     *
     * @throws NullPointerException {@inheritDoc}
     * @since 1.5
     */
    // 判断当前类上是否存在注解类型annotationClass，要求注解类型annotationClass运行时可见（@Retention(RetentionPolicy.RUNTIME)）
    @Override
    public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) {
        return GenericDeclaration.super.isAnnotationPresent(annotationClass);
    }
    
    /*▲ isXXX ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ Class ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Returns the {@code Class} representing the component type of an
     * array.  If this class does not represent an array class this method
     * returns null.
     *
     * @return the {@code Class} representing the component type of this
     * class if this class is an array
     *
     * @see java.lang.reflect.Array
     * @since 1.1
     */
    // 获取数组的组件类型，如int[]返回int，int[][]返回int[]。如果不是数组，则返回空
    public Class<?> getComponentType() {
        // Only return for array types. Storage may be reused for Class for instance types.
        if(isArray()) {
            return componentType;
        } else {
            return null;
        }
    }
    
    /**
     * Returns the {@code Class} representing the direct superclass of the
     * entity (class, interface, primitive type or void) represented by
     * this {@code Class}.  If this {@code Class} represents either the
     * {@code Object} class, an interface, a primitive type, or void, then
     * null is returned.  If this object represents an array class then the
     * {@code Class} object representing the {@code Object} class is
     * returned.
     *
     * @return the direct superclass of the class represented by this object
     */
    // 获取当前类的父类（只识别非泛型类型）
    @HotSpotIntrinsicCandidate
    public native Class<? super T> getSuperclass();
    
    /**
     * Returns the interfaces directly implemented by the class or interface
     * represented by this object.
     *
     * <p>If this object represents a class, the return value is an array
     * containing objects representing all interfaces directly implemented by
     * the class.  The order of the interface objects in the array corresponds
     * to the order of the interface names in the {@code implements} clause of
     * the declaration of the class represented by this object.  For example,
     * given the declaration:
     * <blockquote>
     * {@code class Shimmer implements FloorWax, DessertTopping { ... }}
     * </blockquote>
     * suppose the value of {@code s} is an instance of
     * {@code Shimmer}; the value of the expression:
     * <blockquote>
     * {@code s.getClass().getInterfaces()[0]}
     * </blockquote>
     * is the {@code Class} object that represents interface
     * {@code FloorWax}; and the value of:
     * <blockquote>
     * {@code s.getClass().getInterfaces()[1]}
     * </blockquote>
     * is the {@code Class} object that represents interface
     * {@code DessertTopping}.
     *
     * <p>If this object represents an interface, the array contains objects
     * representing all interfaces directly extended by the interface.  The
     * order of the interface objects in the array corresponds to the order of
     * the interface names in the {@code extends} clause of the declaration of
     * the interface represented by this object.
     *
     * <p>If this object represents a class or interface that implements no
     * interfaces, the method returns an array of length 0.
     *
     * <p>If this object represents a primitive type or void, the method
     * returns an array of length 0.
     *
     * <p>If this {@code Class} object represents an array type, the
     * interfaces {@code Cloneable} and {@code java.io.Serializable} are
     * returned in that order.
     *
     * @return an array of interfaces directly implemented by this class
     */
    // 获取当前类的父接口，不包括父类/父接口实现的接口（只识别非泛型类型）
    public Class<?>[] getInterfaces() {
        // defensively copy before handing over to user code
        return getInterfaces(true);
    }
    
    /**
     * Returns the immediately enclosing class of the underlying
     * class.  If the underlying class is a top level class this
     * method returns {@code null}.
     *
     * @return the immediately enclosing class of the underlying class
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and the caller's
     *                           class loader is not the same as or an ancestor of the class
     *                           loader for the enclosing class and invocation of {@link
     *                           SecurityManager#checkPackageAccess s.checkPackageAccess()}
     *                           denies access to the package of the enclosing class
     * @since 1.5
     */
    // 获取[内部类]所处的外部类（对成员内部类、方法内部类、匿名内部类均有效），如果并非内部类，则返回null
    @CallerSensitive
    public Class<?> getEnclosingClass() throws SecurityException {
        // There are five kinds of classes (or interfaces):
        // a) Top level classes
        // b) Nested classes (static member classes)
        // c) Inner classes (non-static member classes)
        // d) Local classes (named classes declared within a method)
        // e) Anonymous classes
    
        /*
         * JVM Spec 4.7.7:
         * A class must have an EnclosingMethod attribute if and only if it is a local class or an anonymous class.
         */
        EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
        Class<?> enclosingCandidate;
    
        if(enclosingInfo == null) {
            // This is a top level or a nested class or an inner class (a, b, or c)
            enclosingCandidate = getDeclaringClass0();
        } else {
            Class<?> enclosingClass = enclosingInfo.getEnclosingClass();
            // This is a local class or an anonymous class (d or e)
            if(enclosingClass == this || enclosingClass == null) {
                throw new InternalError("Malformed enclosing method information");
            } else {
                enclosingCandidate = enclosingClass;
            }
        }
        
        if(enclosingCandidate != null) {
            SecurityManager sm = System.getSecurityManager();
            if(sm != null) {
                enclosingCandidate.checkPackageAccess(sm, ClassLoader.getClassLoader(Reflection.getCallerClass()), true);
            }
        }
    
        return enclosingCandidate;
    }
    
    /**
     * If the class or interface represented by this {@code Class} object
     * is a member of another class, returns the {@code Class} object
     * representing the class in which it was declared.  This method returns
     * null if this class or interface is not a member of any other class.  If
     * this {@code Class} object represents an array class, a primitive
     * type, or void,then this method returns null.
     *
     * @return the declaring class for this class
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and the caller's
     *                           class loader is not the same as or an ancestor of the class
     *                           loader for the declaring class and invocation of {@link
     *                           SecurityManager#checkPackageAccess s.checkPackageAccess()}
     *                           denies access to the package of the declaring class
     * @since 1.1
     */
    // 获取[成员内部类]所处的外部类(仅对成员内部类有效)，如果并非内部类，则返回null
    @CallerSensitive
    public Class<?> getDeclaringClass() throws SecurityException {
        final Class<?> candidate = getDeclaringClass0();
        if(candidate == null) {
            return candidate;
        }
    
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            candidate.checkPackageAccess(sm, ClassLoader.getClassLoader(Reflection.getCallerClass()), true);
        }
    
        return candidate;
    }
    
    /**
     * Returns an array of {@code Class} objects reflecting all the
     * classes and interfaces declared as members of the class represented by
     * this {@code Class} object. This includes public, protected, default
     * (package) access, and private classes and interfaces declared by the
     * class, but excludes inherited classes and interfaces.  This method
     * returns an array of length 0 if the class declares no classes or
     * interfaces as members, or if this {@code Class} object represents a
     * primitive type, an array class, or void.
     *
     * @return the array of {@code Class} objects representing all the
     * declared members of this class
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and any of the
     *                           following conditions is met:
     *
     *                           <ul>
     *
     *                           <li> the caller's class loader is not the same as the
     *                           class loader of this class and invocation of
     *                           {@link SecurityManager#checkPermission
     *                           s.checkPermission} method with
     *                           {@code RuntimePermission("accessDeclaredMembers")}
     *                           denies access to the declared classes within this class
     *
     *                           <li> the caller's class loader is not the same as or an
     *                           ancestor of the class loader for the current class and
     *                           invocation of {@link SecurityManager#checkPackageAccess
     *                           s.checkPackageAccess()} denies access to the package
     *                           of this class
     *
     *                           </ul>
     * @since 1.1
     */
    // 获取当前类包含的内部类/接口，包含所有权限修饰符修饰的内部接口、内部抽象类、内部实例类，不会继承父类和父接口的内容
    @CallerSensitive
    public Class<?>[] getDeclaredClasses() throws SecurityException {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), false);
        }
    
        return getDeclaredClasses0();
    }
    
    /**
     * Returns an array containing {@code Class} objects representing all
     * the public classes and interfaces that are members of the class
     * represented by this {@code Class} object.  This includes public
     * class and interface members inherited from superclasses and public class
     * and interface members declared by the class.  This method returns an
     * array of length 0 if this {@code Class} object has no public member
     * classes or interfaces.  This method also returns an array of length 0 if
     * this {@code Class} object represents a primitive type, an array
     * class, or void.
     *
     * @return the array of {@code Class} objects representing the public
     * members of this class
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and
     *                           the caller's class loader is not the same as or an
     *                           ancestor of the class loader for the current class and
     *                           invocation of {@link SecurityManager#checkPackageAccess
     *                           s.checkPackageAccess()} denies access to the package
     *                           of this class.
     * @since 1.1
     */
    // 获取当前类包含的内部类/接口，仅包含public修饰的内部接口、内部抽象类、内部实例类，会继承父类内容，但不会继承父接口的内容
    @CallerSensitive
    public Class<?>[] getClasses() {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), false);
        }
        
        // Privileged so this implementation can look at DECLARED classes,
        // something the caller might not have privilege to do.  The code here
        // is allowed to look at DECLARED classes because (1) it does not hand
        // out anything other than public members and (2) public member access
        // has already been ok'd by the SecurityManager.
        
        return AccessController.doPrivileged(new PrivilegedAction<>() {
            public Class<?>[] run() {
                List<Class<?>> list = new ArrayList<>();
                Class<?> currentClass = Class.this;
                while(currentClass != null) {
                    for(Class<?> m : currentClass.getDeclaredClasses()) {
                        if(Modifier.isPublic(m.getModifiers())) {
                            list.add(m);
                        }
                    }
                    currentClass = currentClass.getSuperclass();
                }
                return list.toArray(new Class<?>[0]);
            }
        });
    }
    
    /**
     * Returns the nest host of the <a href=#nest>nest</a> to which the class
     * or interface represented by this {@code Class} object belongs.
     * Every class and interface is a member of exactly one nest.
     * A class or interface that is not recorded as belonging to a nest
     * belongs to the nest consisting only of itself, and is the nest
     * host.
     *
     * <p>Each of the {@code Class} objects representing array types,
     * primitive types, and {@code void} returns {@code this} to indicate
     * that the represented entity belongs to the nest consisting only of
     * itself, and is the nest host.
     *
     * <p>If there is a {@linkplain LinkageError linkage error} accessing
     * the nest host, or if this class or interface is not enumerated as
     * a member of the nest by the nest host, then it is considered to belong
     * to its own nest and {@code this} is returned as the host.
     *
     * @return the nest host of this class or interface
     *
     * @throws SecurityException If the returned class is not the current class, and
     *                           if a security manager, <i>s</i>, is present and the caller's
     *                           class loader is not the same as or an ancestor of the class
     *                           loader for the returned class and invocation of {@link
     *                           SecurityManager#checkPackageAccess s.checkPackageAccess()}
     *                           denies access to the package of the returned class
     * @apiNote A {@code class} file of version 55.0 or greater may record the
     * host of the nest to which it belongs by using the {@code NestHost}
     * attribute (JVMS 4.7.28). Alternatively, a {@code class} file of
     * version 55.0 or greater may act as a nest host by enumerating the nest's
     * other members with the
     * {@code NestMembers} attribute (JVMS 4.7.29).
     * A {@code class} file of version 54.0 or lower does not use these
     * attributes.
     * @jvms 4.7.28 and 4.7.29 NestHost and NestMembers attributes
     * @jvms 5.4.4 Access Control
     * @since 11
     */
    // 与getEnclosingClass()方法语义基本相同，不同点在于如果并非内部类，则返回当前类本身
    @CallerSensitive
    public Class<?> getNestHost() {
        if(isPrimitive() || isArray()) {
            return this;
        }
    
        Class<?> host;
        try {
            host = getNestHost0();
        } catch(LinkageError e) {
            // if we couldn't load our nest-host then we act as-if we have no nest-host attribute
            return this;
        }
    
        // if null then nest membership validation failed, so we act as-if we have no nest-host attribute
        if(host == null || host == this) {
            return this;
        }
    
        // returning a different class requires a security check
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkPackageAccess(sm, ClassLoader.getClassLoader(Reflection.getCallerClass()), true);
        }
    
        return host;
    }
    
    /**
     * Returns an array containing {@code Class} objects representing all the
     * classes and interfaces that are members of the nest to which the class
     * or interface represented by this {@code Class} object belongs.
     * The {@linkplain #getNestHost() nest host} of that nest is the zeroth
     * element of the array. Subsequent elements represent any classes or
     * interfaces that are recorded by the nest host as being members of
     * the nest; the order of such elements is unspecified. Duplicates are
     * permitted.
     * If the nest host of that nest does not enumerate any members, then the
     * array has a single element containing {@code this}.
     *
     * <p>Each of the {@code Class} objects representing array types,
     * primitive types, and {@code void} returns an array containing only
     * {@code this}.
     *
     * <p>This method validates that, for each class or interface which is
     * recorded as a member of the nest by the nest host, that class or
     * interface records itself as a member of that same nest. Any exceptions
     * that occur during this validation are rethrown by this method.
     *
     * @return an array of all classes and interfaces in the same nest as
     * this class
     *
     * @throws LinkageError      If there is any problem loading or validating a nest member or
     *                           its nest host
     * @throws SecurityException If any returned class is not the current class, and
     *                           if a security manager, <i>s</i>, is present and the caller's
     *                           class loader is not the same as or an ancestor of the class
     *                           loader for that returned class and invocation of {@link
     *                           SecurityManager#checkPackageAccess s.checkPackageAccess()}
     *                           denies access to the package of that returned class
     * @see #getNestHost()
     * @since 11
     */
    // 与getDeclaredClasses()方法语义基本相同，不同点在于返回的数组首元素是当前类本身
    @CallerSensitive
    public Class<?>[] getNestMembers() {
        if(isPrimitive() || isArray()) {
            return new Class<?>[]{this};
        }
    
        Class<?>[] members = getNestMembers0();
        
        // Can't actually enable this due to bootstrapping issues assert(members.length != 1 || members[0] == this); expected invariant from VM
        
        if(members.length>1) {
            // If we return anything other than the current class we need a security check
            SecurityManager sm = System.getSecurityManager();
            if(sm != null) {
                checkPackageAccess(sm, ClassLoader.getClassLoader(Reflection.getCallerClass()), true);
            }
        }
    
        return members;
    }
    
    /*▲ Class ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ 泛型 ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Returns the {@code Type} representing the direct superclass of
     * the entity (class, interface, primitive type or void) represented by
     * this {@code Class}.
     *
     * <p>If the superclass is a parameterized type, the {@code Type}
     * object returned must accurately reflect the actual type
     * parameters used in the source code. The parameterized type
     * representing the superclass is created if it had not been
     * created before. See the declaration of {@link
     * java.lang.reflect.ParameterizedType ParameterizedType} for the
     * semantics of the creation process for parameterized types.  If
     * this {@code Class} represents either the {@code Object}
     * class, an interface, a primitive type, or void, then null is
     * returned.  If this object represents an array class then the
     * {@code Class} object representing the {@code Object} class is
     * returned.
     *
     * @return the direct superclass of the class represented by this object
     *
     * @throws java.lang.reflect.GenericSignatureFormatError         if the generic
     *                                                               class signature does not conform to the format specified in
     *                                                               <cite>The Java&trade; Virtual Machine Specification</cite>
     * @throws TypeNotPresentException                               if the generic superclass
     *                                                               refers to a non-existent type declaration
     * @throws java.lang.reflect.MalformedParameterizedTypeException if the
     *                                                               generic superclass refers to a parameterized type that cannot be
     *                                                               instantiated  for any reason
     * @since 1.5
     */
    // 获取当前类的父类（可识别泛型类型和非泛型类型）
    public Type getGenericSuperclass() {
        ClassRepository info = getGenericInfo();
        if(info == null) {
            return getSuperclass();
        }
        
        // Historical irregularity:
        // Generic signature marks interfaces with superclass = Object but this API returns null for interfaces
        if(isInterface()) {
            return null;
        }
        
        return info.getSuperclass();
    }
    
    /**
     * Returns the {@code Type}s representing the interfaces
     * directly implemented by the class or interface represented by
     * this object.
     *
     * <p>If a superinterface is a parameterized type, the
     * {@code Type} object returned for it must accurately reflect
     * the actual type parameters used in the source code. The
     * parameterized type representing each superinterface is created
     * if it had not been created before. See the declaration of
     * {@link java.lang.reflect.ParameterizedType ParameterizedType}
     * for the semantics of the creation process for parameterized
     * types.
     *
     * <p>If this object represents a class, the return value is an array
     * containing objects representing all interfaces directly implemented by
     * the class.  The order of the interface objects in the array corresponds
     * to the order of the interface names in the {@code implements} clause of
     * the declaration of the class represented by this object.
     *
     * <p>If this object represents an interface, the array contains objects
     * representing all interfaces directly extended by the interface.  The
     * order of the interface objects in the array corresponds to the order of
     * the interface names in the {@code extends} clause of the declaration of
     * the interface represented by this object.
     *
     * <p>If this object represents a class or interface that implements no
     * interfaces, the method returns an array of length 0.
     *
     * <p>If this object represents a primitive type or void, the method
     * returns an array of length 0.
     *
     * <p>If this {@code Class} object represents an array type, the
     * interfaces {@code Cloneable} and {@code java.io.Serializable} are
     * returned in that order.
     *
     * @return an array of interfaces directly implemented by this class
     *
     * @throws java.lang.reflect.GenericSignatureFormatError         if the generic class signature does not conform to the format
     *                                                               specified in
     *                                                               <cite>The Java&trade; Virtual Machine Specification</cite>
     * @throws TypeNotPresentException                               if any of the generic
     *                                                               superinterfaces refers to a non-existent type declaration
     * @throws java.lang.reflect.MalformedParameterizedTypeException if any of the generic superinterfaces refer to a parameterized
     *                                                               type that cannot be instantiated for any reason
     * @since 1.5
     */
    // 获取当前类的父接口（可识别泛型类型和非泛型类型）
    public Type[] getGenericInterfaces() {
        ClassRepository info = getGenericInfo();
        return (info == null) ? getInterfaces() : info.getSuperInterfaces();
    }
    
    /**
     * Returns an array of {@code TypeVariable} objects that represent the
     * type variables declared by the generic declaration represented by this
     * {@code GenericDeclaration} object, in declaration order.  Returns an
     * array of length 0 if the underlying generic declaration declares no type
     * variables.
     *
     * @return an array of {@code TypeVariable} objects that represent
     * the type variables declared by this generic declaration
     *
     * @throws java.lang.reflect.GenericSignatureFormatError if the generic
     *                                                       signature of this generic declaration does not conform to
     *                                                       the format specified in
     *                                                       <cite>The Java&trade; Virtual Machine Specification</cite>
     * @since 1.5
     */
    // 返回generic type中的type variable，如：Map<K, V>中的K和V
    @SuppressWarnings("unchecked")
    public TypeVariable<Class<T>>[] getTypeParameters() {
        ClassRepository info = getGenericInfo();
        if(info != null) {
            return (TypeVariable<Class<T>>[]) info.getTypeParameters();
        } else {
            return (TypeVariable<Class<T>>[]) new TypeVariable<?>[0];
        }
    }
    
    /*▲ 泛型 ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ Constructor ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /* 构造器不属于成员，不能被子类继承 */
    
    /**
     * Returns an array containing {@code Constructor} objects reflecting
     * all the public constructors of the class represented by this
     * {@code Class} object.  An array of length 0 is returned if the
     * class has no public constructors, or if the class is an array class, or
     * if the class reflects a primitive type or void.
     *
     * Note that while this method returns an array of {@code
     * Constructor<T>} objects (that is an array of constructors from
     * this class), the return type of this method is {@code
     * Constructor<?>[]} and <em>not</em> {@code Constructor<T>[]} as
     * might be expected.  This less informative return type is
     * necessary since after being returned from this method, the
     * array could be modified to hold {@code Constructor} objects for
     * different classes, which would violate the type guarantees of
     * {@code Constructor<T>[]}.
     *
     * @return the array of {@code Constructor} objects representing the
     * public constructors of this class
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and
     *                           the caller's class loader is not the same as or an
     *                           ancestor of the class loader for the current class and
     *                           invocation of {@link SecurityManager#checkPackageAccess
     *                           s.checkPackageAccess()} denies access to the package
     *                           of this class.
     * @since 1.1
     */
    // 返回当前类中所有public构造器，但不包括父类中的构造器
    @CallerSensitive
    public Constructor<?>[] getConstructors() throws SecurityException {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true);
        }
    
        return copyConstructors(privateGetDeclaredConstructors(true));
    }
    
    /**
     * Returns a {@code Constructor} object that reflects the specified
     * public constructor of the class represented by this {@code Class}
     * object. The {@code parameterTypes} parameter is an array of
     * {@code Class} objects that identify the constructor's formal
     * parameter types, in declared order.
     *
     * If this {@code Class} object represents an inner class
     * declared in a non-static context, the formal parameter types
     * include the explicit enclosing instance as the first parameter.
     *
     * <p> The constructor to reflect is the public constructor of the class
     * represented by this {@code Class} object whose formal parameter
     * types match those specified by {@code parameterTypes}.
     *
     * @param parameterTypes the parameter array
     *
     * @return the {@code Constructor} object of the public constructor that
     * matches the specified {@code parameterTypes}
     *
     * @throws NoSuchMethodException if a matching method is not found.
     * @throws SecurityException     If a security manager, <i>s</i>, is present and
     *                               the caller's class loader is not the same as or an
     *                               ancestor of the class loader for the current class and
     *                               invocation of {@link SecurityManager#checkPackageAccess
     *                               s.checkPackageAccess()} denies access to the package
     *                               of this class.
     * @since 1.1
     */
    // 返回当前类中指定形参的public构造器，但不包括父类中的构造器
    @CallerSensitive
    public Constructor<T> getConstructor(Class<?>... parameterTypes) throws NoSuchMethodException, SecurityException {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true);
        }
    
        return getReflectionFactory().copyConstructor(getConstructor0(parameterTypes, Member.PUBLIC));
    }
    
    /**
     * Returns an array of {@code Constructor} objects reflecting all the
     * constructors declared by the class represented by this
     * {@code Class} object. These are public, protected, default
     * (package) access, and private constructors.  The elements in the array
     * returned are not sorted and are not in any particular order.  If the
     * class has a default constructor, it is included in the returned array.
     * This method returns an array of length 0 if this {@code Class}
     * object represents an interface, a primitive type, an array class, or
     * void.
     *
     * <p> See <em>The Java Language Specification</em>, section 8.2.
     *
     * @return the array of {@code Constructor} objects representing all the
     * declared constructors of this class
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and any of the
     *                           following conditions is met:
     *
     *                           <ul>
     *
     *                           <li> the caller's class loader is not the same as the
     *                           class loader of this class and invocation of
     *                           {@link SecurityManager#checkPermission
     *                           s.checkPermission} method with
     *                           {@code RuntimePermission("accessDeclaredMembers")}
     *                           denies access to the declared constructors within this class
     *
     *                           <li> the caller's class loader is not the same as or an
     *                           ancestor of the class loader for the current class and
     *                           invocation of {@link SecurityManager#checkPackageAccess
     *                           s.checkPackageAccess()} denies access to the package
     *                           of this class
     *
     *                           </ul>
     * @since 1.1
     */
    // 返回当前类中所有构造器，但不包括父类中的构造器
    @CallerSensitive
    public Constructor<?>[] getDeclaredConstructors() throws SecurityException {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true);
        }
    
        return copyConstructors(privateGetDeclaredConstructors(false));
    }
    
    /**
     * Returns a {@code Constructor} object that reflects the specified
     * constructor of the class or interface represented by this
     * {@code Class} object.  The {@code parameterTypes} parameter is
     * an array of {@code Class} objects that identify the constructor's
     * formal parameter types, in declared order.
     *
     * If this {@code Class} object represents an inner class
     * declared in a non-static context, the formal parameter types
     * include the explicit enclosing instance as the first parameter.
     *
     * @param parameterTypes the parameter array
     *
     * @return The {@code Constructor} object for the constructor with the
     * specified parameter list
     *
     * @throws NoSuchMethodException if a matching method is not found.
     * @throws SecurityException     If a security manager, <i>s</i>, is present and any of the
     *                               following conditions is met:
     *
     *                               <ul>
     *
     *                               <li> the caller's class loader is not the same as the
     *                               class loader of this class and invocation of
     *                               {@link SecurityManager#checkPermission
     *                               s.checkPermission} method with
     *                               {@code RuntimePermission("accessDeclaredMembers")}
     *                               denies access to the declared constructor
     *
     *                               <li> the caller's class loader is not the same as or an
     *                               ancestor of the class loader for the current class and
     *                               invocation of {@link SecurityManager#checkPackageAccess
     *                               s.checkPackageAccess()} denies access to the package
     *                               of this class
     *
     *                               </ul>
     * @since 1.1
     */
    // 返回当前类中指定形参的构造器，但不包括父类中的构造器
    @CallerSensitive
    public Constructor<T> getDeclaredConstructor(Class<?>... parameterTypes) throws NoSuchMethodException, SecurityException {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true);
        }
        
        return getReflectionFactory().copyConstructor(getConstructor0(parameterTypes, Member.DECLARED));
    }
    
    /**
     * If this {@code Class} object represents a local or anonymous
     * class within a constructor, returns a {@link
     * java.lang.reflect.Constructor Constructor} object representing
     * the immediately enclosing constructor of the underlying
     * class. Returns {@code null} otherwise.  In particular, this
     * method returns {@code null} if the underlying class is a local
     * or anonymous class immediately enclosed by a type declaration,
     * instance initializer or static initializer.
     *
     * @return the immediately enclosing constructor of the underlying class, if
     * that class is a local or anonymous class; otherwise {@code null}.
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and any of the
     *                           following conditions is met:
     *
     *                           <ul>
     *
     *                           <li> the caller's class loader is not the same as the
     *                           class loader of the enclosing class and invocation of
     *                           {@link SecurityManager#checkPermission
     *                           s.checkPermission} method with
     *                           {@code RuntimePermission("accessDeclaredMembers")}
     *                           denies access to the constructors within the enclosing class
     *
     *                           <li> the caller's class loader is not the same as or an
     *                           ancestor of the class loader for the enclosing class and
     *                           invocation of {@link SecurityManager#checkPackageAccess
     *                           s.checkPackageAccess()} denies access to the package
     *                           of the enclosing class
     *
     *                           </ul>
     * @since 1.5
     */
    // 返回构造器内部类或定义在构造器内部的匿名类所处的构造器。如果该类定义在构造器外部，则调用此方法时返回null
    @CallerSensitive
    public Constructor<?> getEnclosingConstructor() throws SecurityException {
        EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
    
        if(enclosingInfo == null) {
            return null;
        } else {
            if(!enclosingInfo.isConstructor()) {
                return null;
            }
        
            ConstructorRepository typeInfo = ConstructorRepository.make(enclosingInfo.getDescriptor(), getFactory());
            Type[] parameterTypes = typeInfo.getParameterTypes();
            Class<?>[] parameterClasses = new Class<?>[parameterTypes.length];
        
            // Convert Types to Classes; returned types *should*
            // be class objects since the methodDescriptor's used
            // don't have generics information
            for(int i = 0; i<parameterClasses.length; i++) {
                parameterClasses[i] = toClass(parameterTypes[i]);
            }
            
            // Perform access check
            final Class<?> enclosingCandidate = enclosingInfo.getEnclosingClass();
            SecurityManager sm = System.getSecurityManager();
            if(sm != null) {
                enclosingCandidate.checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true);
            }
            
            Constructor<?>[] candidates = enclosingCandidate.privateGetDeclaredConstructors(false);
            /*
             * Loop over all declared constructors; match number
             * of and type of parameters.
             */
            ReflectionFactory fact = getReflectionFactory();
            for(Constructor<?> c : candidates) {
                if(arrayContentsEq(parameterClasses, fact.getExecutableSharedParameterTypes(c))) {
                    return fact.copyConstructor(c);
                }
            }
            
            throw new InternalError("Enclosing constructor not found");
        }
    }
    
    /*▲ Constructor ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ Method ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Returns an array containing {@code Method} objects reflecting all the
     * public methods of the class or interface represented by this {@code
     * Class} object, including those declared by the class or interface and
     * those inherited from superclasses and superinterfaces.
     *
     * <p> If this {@code Class} object represents an array type, then the
     * returned array has a {@code Method} object for each of the public
     * methods inherited by the array type from {@code Object}. It does not
     * contain a {@code Method} object for {@code clone()}.
     *
     * <p> If this {@code Class} object represents an interface then the
     * returned array does not contain any implicitly declared methods from
     * {@code Object}. Therefore, if no methods are explicitly declared in
     * this interface or any of its superinterfaces then the returned array
     * has length 0. (Note that a {@code Class} object which represents a class
     * always has public methods, inherited from {@code Object}.)
     *
     * <p> The returned array never contains methods with names "{@code <init>}"
     * or "{@code <clinit>}".
     *
     * <p> The elements in the returned array are not sorted and are not in any
     * particular order.
     *
     * <p> Generally, the result is computed as with the following 4 step algorithm.
     * Let C be the class or interface represented by this {@code Class} object:
     * <ol>
     * <li> A union of methods is composed of:
     * <ol type="a">
     * <li> C's declared public instance and static methods as returned by
     * {@link #getDeclaredMethods()} and filtered to include only public
     * methods.</li>
     * <li> If C is a class other than {@code Object}, then include the result
     * of invoking this algorithm recursively on the superclass of C.</li>
     * <li> Include the results of invoking this algorithm recursively on all
     * direct superinterfaces of C, but include only instance methods.</li>
     * </ol></li>
     * <li> Union from step 1 is partitioned into subsets of methods with same
     * signature (name, parameter types) and return type.</li>
     * <li> Within each such subset only the most specific methods are selected.
     * Let method M be a method from a set of methods with same signature
     * and return type. M is most specific if there is no such method
     * N != M from the same set, such that N is more specific than M.
     * N is more specific than M if:
     * <ol type="a">
     * <li> N is declared by a class and M is declared by an interface; or</li>
     * <li> N and M are both declared by classes or both by interfaces and
     * N's declaring type is the same as or a subtype of M's declaring type
     * (clearly, if M's and N's declaring types are the same type, then
     * M and N are the same method).</li>
     * </ol></li>
     * <li> The result of this algorithm is the union of all selected methods from
     * step 3.</li>
     * </ol>
     *
     * @return the array of {@code Method} objects representing the
     * public methods of this class
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and
     *                           the caller's class loader is not the same as or an
     *                           ancestor of the class loader for the current class and
     *                           invocation of {@link SecurityManager#checkPackageAccess
     *                           s.checkPackageAccess()} denies access to the package
     *                           of this class.
     * @apiNote There may be more than one method with a particular name
     * and parameter types in a class because while the Java language forbids a
     * class to declare multiple methods with the same signature but different
     * return types, the Java virtual machine does not.  This
     * increased flexibility in the virtual machine can be used to
     * implement various language features.  For example, covariant
     * returns can be implemented with {@linkplain
     * java.lang.reflect.Method#isBridge bridge methods}; the bridge
     * method and the overriding method would have the same
     * signature but different return types.
     * @jls 8.2 Class Members
     * @jls 8.4 Method Declarations
     * @since 1.1
     */
    /*
     * 返回当前类中所有public方法，包括父类/父接口中的public方法
     * 特别地，如果当前类是实例类，则无法获取父接口中的static方法（该方法虽然是public，但只有父接口可视）
     * 对于父接口中的default方法，无论子类是否重写，这里均可以获取到它
     */
    @CallerSensitive
    public Method[] getMethods() throws SecurityException {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true);
        }
    
        return copyMethods(privateGetPublicMethods());
    }
    
    /**
     * Returns a {@code Method} object that reflects the specified public
     * member method of the class or interface represented by this
     * {@code Class} object. The {@code name} parameter is a
     * {@code String} specifying the simple name of the desired method. The
     * {@code parameterTypes} parameter is an array of {@code Class}
     * objects that identify the method's formal parameter types, in declared
     * order. If {@code parameterTypes} is {@code null}, it is
     * treated as if it were an empty array.
     *
     * <p> If this {@code Class} object represents an array type, then this
     * method finds any public method inherited by the array type from
     * {@code Object} except method {@code clone()}.
     *
     * <p> If this {@code Class} object represents an interface then this
     * method does not find any implicitly declared method from
     * {@code Object}. Therefore, if no methods are explicitly declared in
     * this interface or any of its superinterfaces, then this method does not
     * find any method.
     *
     * <p> This method does not find any method with name "{@code <init>}" or
     * "{@code <clinit>}".
     *
     * <p> Generally, the method to be reflected is determined by the 4 step
     * algorithm that follows.
     * Let C be the class or interface represented by this {@code Class} object:
     * <ol>
     * <li> A union of methods is composed of:
     * <ol type="a">
     * <li> C's declared public instance and static methods as returned by
     * {@link #getDeclaredMethods()} and filtered to include only public
     * methods that match given {@code name} and {@code parameterTypes}</li>
     * <li> If C is a class other than {@code Object}, then include the result
     * of invoking this algorithm recursively on the superclass of C.</li>
     * <li> Include the results of invoking this algorithm recursively on all
     * direct superinterfaces of C, but include only instance methods.</li>
     * </ol></li>
     * <li> This union is partitioned into subsets of methods with same
     * return type (the selection of methods from step 1 also guarantees that
     * they have the same method name and parameter types).</li>
     * <li> Within each such subset only the most specific methods are selected.
     * Let method M be a method from a set of methods with same VM
     * signature (return type, name, parameter types).
     * M is most specific if there is no such method N != M from the same
     * set, such that N is more specific than M. N is more specific than M
     * if:
     * <ol type="a">
     * <li> N is declared by a class and M is declared by an interface; or</li>
     * <li> N and M are both declared by classes or both by interfaces and
     * N's declaring type is the same as or a subtype of M's declaring type
     * (clearly, if M's and N's declaring types are the same type, then
     * M and N are the same method).</li>
     * </ol></li>
     * <li> The result of this algorithm is chosen arbitrarily from the methods
     * with most specific return type among all selected methods from step 3.
     * Let R be a return type of a method M from the set of all selected methods
     * from step 3. M is a method with most specific return type if there is
     * no such method N != M from the same set, having return type S != R,
     * such that S is a subtype of R as determined by
     * R.class.{@link #isAssignableFrom}(S.class).
     * </ol>
     *
     * @param name           the name of the method
     * @param parameterTypes the list of parameters
     *
     * @return the {@code Method} object that matches the specified
     * {@code name} and {@code parameterTypes}
     *
     * @throws NoSuchMethodException if a matching method is not found
     *                               or if the name is "&lt;init&gt;"or "&lt;clinit&gt;".
     * @throws NullPointerException  if {@code name} is {@code null}
     * @throws SecurityException     If a security manager, <i>s</i>, is present and
     *                               the caller's class loader is not the same as or an
     *                               ancestor of the class loader for the current class and
     *                               invocation of {@link SecurityManager#checkPackageAccess
     *                               s.checkPackageAccess()} denies access to the package
     *                               of this class.
     * @apiNote There may be more than one method with matching name and
     * parameter types in a class because while the Java language forbids a
     * class to declare multiple methods with the same signature but different
     * return types, the Java virtual machine does not.  This
     * increased flexibility in the virtual machine can be used to
     * implement various language features.  For example, covariant
     * returns can be implemented with {@linkplain
     * java.lang.reflect.Method#isBridge bridge methods}; the bridge
     * method and the overriding method would have the same
     * signature but different return types. This method would return the
     * overriding method as it would have a more specific return type.
     * @jls 8.2 Class Members
     * @jls 8.4 Method Declarations
     * @since 1.1
     */
    /*
     * 返回当前类中指定名称和形参的public方法，包括父类/父接口中的public方法
     * 特别地，如果当前类是实例类，则无法获取父接口中的static方法（该方法虽然是public，但只有父接口可视）
     * 对于父接口中的default方法，无论子类是否重写，这里均可以获取到它
     */
    @CallerSensitive
    public Method getMethod(String name, Class<?>... parameterTypes) throws NoSuchMethodException, SecurityException {
        Objects.requireNonNull(name);
    
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true);
        }
    
        Method method = getMethod0(name, parameterTypes);
        if(method == null) {
            throw new NoSuchMethodException(methodToString(name, parameterTypes));
        }
    
        return getReflectionFactory().copyMethod(method);
    }
    
    /**
     * Returns an array containing {@code Method} objects reflecting all the
     * declared methods of the class or interface represented by this {@code
     * Class} object, including public, protected, default (package)
     * access, and private methods, but excluding inherited methods.
     *
     * <p> If this {@code Class} object represents a type that has multiple
     * declared methods with the same name and parameter types, but different
     * return types, then the returned array has a {@code Method} object for
     * each such method.
     *
     * <p> If this {@code Class} object represents a type that has a class
     * initialization method {@code <clinit>}, then the returned array does
     * <em>not</em> have a corresponding {@code Method} object.
     *
     * <p> If this {@code Class} object represents a class or interface with no
     * declared methods, then the returned array has length 0.
     *
     * <p> If this {@code Class} object represents an array type, a primitive
     * type, or void, then the returned array has length 0.
     *
     * <p> The elements in the returned array are not sorted and are not in any
     * particular order.
     *
     * @return the array of {@code Method} objects representing all the
     * declared methods of this class
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and any of the
     *                           following conditions is met:
     *
     *                           <ul>
     *
     *                           <li> the caller's class loader is not the same as the
     *                           class loader of this class and invocation of
     *                           {@link SecurityManager#checkPermission
     *                           s.checkPermission} method with
     *                           {@code RuntimePermission("accessDeclaredMembers")}
     *                           denies access to the declared methods within this class
     *
     *                           <li> the caller's class loader is not the same as or an
     *                           ancestor of the class loader for the current class and
     *                           invocation of {@link SecurityManager#checkPackageAccess
     *                           s.checkPackageAccess()} denies access to the package
     *                           of this class
     *
     *                           </ul>
     * @jls 8.2 Class Members
     * @jls 8.4 Method Declarations
     * @since 1.1
     */
    // 返回当前类中所有方法，但不包括父类/父接口中的方法
    @CallerSensitive
    public Method[] getDeclaredMethods() throws SecurityException {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true);
        }
    
        return copyMethods(privateGetDeclaredMethods(false));
    }
    
    /**
     * Returns a {@code Method} object that reflects the specified
     * declared method of the class or interface represented by this
     * {@code Class} object. The {@code name} parameter is a
     * {@code String} that specifies the simple name of the desired
     * method, and the {@code parameterTypes} parameter is an array of
     * {@code Class} objects that identify the method's formal parameter
     * types, in declared order.  If more than one method with the same
     * parameter types is declared in a class, and one of these methods has a
     * return type that is more specific than any of the others, that method is
     * returned; otherwise one of the methods is chosen arbitrarily.  If the
     * name is "&lt;init&gt;"or "&lt;clinit&gt;" a {@code NoSuchMethodException}
     * is raised.
     *
     * <p> If this {@code Class} object represents an array type, then this
     * method does not find the {@code clone()} method.
     *
     * @param name           the name of the method
     * @param parameterTypes the parameter array
     *
     * @return the {@code Method} object for the method of this class
     * matching the specified name and parameters
     *
     * @throws NoSuchMethodException if a matching method is not found.
     * @throws NullPointerException  if {@code name} is {@code null}
     * @throws SecurityException     If a security manager, <i>s</i>, is present and any of the
     *                               following conditions is met:
     *
     *                               <ul>
     *
     *                               <li> the caller's class loader is not the same as the
     *                               class loader of this class and invocation of
     *                               {@link SecurityManager#checkPermission
     *                               s.checkPermission} method with
     *                               {@code RuntimePermission("accessDeclaredMembers")}
     *                               denies access to the declared method
     *
     *                               <li> the caller's class loader is not the same as or an
     *                               ancestor of the class loader for the current class and
     *                               invocation of {@link SecurityManager#checkPackageAccess
     *                               s.checkPackageAccess()} denies access to the package
     *                               of this class
     *
     *                               </ul>
     * @jls 8.2 Class Members
     * @jls 8.4 Method Declarations
     * @since 1.1
     */
    // 返回当前类中指定名称和形参的方法，但不包括父类/父接口中的方法
    @CallerSensitive
    public Method getDeclaredMethod(String name, Class<?>... parameterTypes) throws NoSuchMethodException, SecurityException {
        Objects.requireNonNull(name);
    
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true);
        }
    
        Method method = searchMethods(privateGetDeclaredMethods(false), name, parameterTypes);
        if(method == null) {
            throw new NoSuchMethodException(methodToString(name, parameterTypes));
        }
    
        return getReflectionFactory().copyMethod(method);
    }
    
    /**
     * If this {@code Class} object represents a local or anonymous
     * class within a method, returns a {@link
     * java.lang.reflect.Method Method} object representing the
     * immediately enclosing method of the underlying class. Returns
     * {@code null} otherwise.
     *
     * In particular, this method returns {@code null} if the underlying
     * class is a local or anonymous class immediately enclosed by a type
     * declaration, instance initializer or static initializer.
     *
     * @return the immediately enclosing method of the underlying class, if
     * that class is a local or anonymous class; otherwise {@code null}.
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and any of the
     *                           following conditions is met:
     *
     *                           <ul>
     *
     *                           <li> the caller's class loader is not the same as the
     *                           class loader of the enclosing class and invocation of
     *                           {@link SecurityManager#checkPermission
     *                           s.checkPermission} method with
     *                           {@code RuntimePermission("accessDeclaredMembers")}
     *                           denies access to the methods within the enclosing class
     *
     *                           <li> the caller's class loader is not the same as or an
     *                           ancestor of the class loader for the enclosing class and
     *                           invocation of {@link SecurityManager#checkPackageAccess
     *                           s.checkPackageAccess()} denies access to the package
     *                           of the enclosing class
     *
     *                           </ul>
     * @since 1.5
     */
    // 返回方法内部类或定义在方法内部的匿名类所处的外部方法。如果该类定义在方法外部，则调用此方法时返回null
    @CallerSensitive
    public Method getEnclosingMethod() throws SecurityException {
        EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
    
        if(enclosingInfo == null) {
            return null;
        } else {
            if(!enclosingInfo.isMethod()) {
                return null;
            }
        
            MethodRepository typeInfo = MethodRepository.make(enclosingInfo.getDescriptor(), getFactory());
            Class<?> returnType = toClass(typeInfo.getReturnType());
            Type[] parameterTypes = typeInfo.getParameterTypes();
            Class<?>[] parameterClasses = new Class<?>[parameterTypes.length];
        
            // Convert Types to Classes; returned types *should*
            // be class objects since the methodDescriptor's used
            // don't have generics information
            for(int i = 0; i<parameterClasses.length; i++)
                parameterClasses[i] = toClass(parameterTypes[i]);
            
            // Perform access check
            final Class<?> enclosingCandidate = enclosingInfo.getEnclosingClass();
            SecurityManager sm = System.getSecurityManager();
            if(sm != null) {
                enclosingCandidate.checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true);
            }
            Method[] candidates = enclosingCandidate.privateGetDeclaredMethods(false);
            
            /*
             * Loop over all declared methods; match method name,
             * number of and type of parameters, *and* return
             * type.  Matching return type is also necessary
             * because of covariant returns, etc.
             */
            ReflectionFactory fact = getReflectionFactory();
            for(Method m : candidates) {
                if(m.getName().equals(enclosingInfo.getName()) && arrayContentsEq(parameterClasses, fact.getExecutableSharedParameterTypes(m))) {
                    // finally, check return type
                    if(m.getReturnType().equals(returnType)) {
                        return fact.copyMethod(m);
                    }
                }
            }
            
            throw new InternalError("Enclosing method not found");
        }
    }
    
    /*▲ Method ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ Field ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Returns an array containing {@code Field} objects reflecting all
     * the accessible public fields of the class or interface represented by
     * this {@code Class} object.
     *
     * <p> If this {@code Class} object represents a class or interface with
     * no accessible public fields, then this method returns an array of length
     * 0.
     *
     * <p> If this {@code Class} object represents a class, then this method
     * returns the public fields of the class and of all its superclasses and
     * superinterfaces.
     *
     * <p> If this {@code Class} object represents an interface, then this
     * method returns the fields of the interface and of all its
     * superinterfaces.
     *
     * <p> If this {@code Class} object represents an array type, a primitive
     * type, or void, then this method returns an array of length 0.
     *
     * <p> The elements in the returned array are not sorted and are not in any
     * particular order.
     *
     * @return the array of {@code Field} objects representing the
     * public fields
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and
     *                           the caller's class loader is not the same as or an
     *                           ancestor of the class loader for the current class and
     *                           invocation of {@link SecurityManager#checkPackageAccess
     *                           s.checkPackageAccess()} denies access to the package
     *                           of this class.
     * @jls 8.2 Class Members
     * @jls 8.3 Field Declarations
     * @since 1.1
     */
    // 返回当前类中所有public字段，包括父类/父接口中的public字段
    @CallerSensitive
    public Field[] getFields() throws SecurityException {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true);
        }
    
        return copyFields(privateGetPublicFields());
    }
    
    /**
     * Returns a {@code Field} object that reflects the specified public member
     * field of the class or interface represented by this {@code Class}
     * object. The {@code name} parameter is a {@code String} specifying the
     * simple name of the desired field.
     *
     * <p> The field to be reflected is determined by the algorithm that
     * follows.  Let C be the class or interface represented by this object:
     *
     * <OL>
     * <LI> If C declares a public field with the name specified, that is the
     * field to be reflected.</LI>
     * <LI> If no field was found in step 1 above, this algorithm is applied
     * recursively to each direct superinterface of C. The direct
     * superinterfaces are searched in the order they were declared.</LI>
     * <LI> If no field was found in steps 1 and 2 above, and C has a
     * superclass S, then this algorithm is invoked recursively upon S.
     * If C has no superclass, then a {@code NoSuchFieldException}
     * is thrown.</LI>
     * </OL>
     *
     * <p> If this {@code Class} object represents an array type, then this
     * method does not find the {@code length} field of the array type.
     *
     * @param name the field name
     *
     * @return the {@code Field} object of this class specified by
     * {@code name}
     *
     * @throws NoSuchFieldException if a field with the specified name is
     *                              not found.
     * @throws NullPointerException if {@code name} is {@code null}
     * @throws SecurityException    If a security manager, <i>s</i>, is present and
     *                              the caller's class loader is not the same as or an
     *                              ancestor of the class loader for the current class and
     *                              invocation of {@link SecurityManager#checkPackageAccess
     *                              s.checkPackageAccess()} denies access to the package
     *                              of this class.
     * @jls 8.2 Class Members
     * @jls 8.3 Field Declarations
     * @since 1.1
     */
    // 返回当前类中指定名称的public字段，包括父类/父接口中的public字段
    @CallerSensitive
    public Field getField(String name) throws NoSuchFieldException, SecurityException {
        Objects.requireNonNull(name);
    
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true);
        }
    
        Field field = getField0(name);
        if(field == null) {
            throw new NoSuchFieldException(name);
        }
    
        return getReflectionFactory().copyField(field);
    }
    
    /**
     * Returns an array of {@code Field} objects reflecting all the fields
     * declared by the class or interface represented by this
     * {@code Class} object. This includes public, protected, default
     * (package) access, and private fields, but excludes inherited fields.
     *
     * <p> If this {@code Class} object represents a class or interface with no
     * declared fields, then this method returns an array of length 0.
     *
     * <p> If this {@code Class} object represents an array type, a primitive
     * type, or void, then this method returns an array of length 0.
     *
     * <p> The elements in the returned array are not sorted and are not in any
     * particular order.
     *
     * @return the array of {@code Field} objects representing all the
     * declared fields of this class
     *
     * @throws SecurityException If a security manager, <i>s</i>, is present and any of the
     *                           following conditions is met:
     *
     *                           <ul>
     *
     *                           <li> the caller's class loader is not the same as the
     *                           class loader of this class and invocation of
     *                           {@link SecurityManager#checkPermission
     *                           s.checkPermission} method with
     *                           {@code RuntimePermission("accessDeclaredMembers")}
     *                           denies access to the declared fields within this class
     *
     *                           <li> the caller's class loader is not the same as or an
     *                           ancestor of the class loader for the current class and
     *                           invocation of {@link SecurityManager#checkPackageAccess
     *                           s.checkPackageAccess()} denies access to the package
     *                           of this class
     *
     *                           </ul>
     * @jls 8.2 Class Members
     * @jls 8.3 Field Declarations
     * @since 1.1
     */
    // 返回当前类中所有字段，但不包括父类/父接口中的字段
    @CallerSensitive
    public Field[] getDeclaredFields() throws SecurityException {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true);
        }
    
        return copyFields(privateGetDeclaredFields(false));
    }
    
    /**
     * Returns a {@code Field} object that reflects the specified declared
     * field of the class or interface represented by this {@code Class}
     * object. The {@code name} parameter is a {@code String} that specifies
     * the simple name of the desired field.
     *
     * <p> If this {@code Class} object represents an array type, then this
     * method does not find the {@code length} field of the array type.
     *
     * @param name the name of the field
     *
     * @return the {@code Field} object for the specified field in this
     * class
     *
     * @throws NoSuchFieldException if a field with the specified name is
     *                              not found.
     * @throws NullPointerException if {@code name} is {@code null}
     * @throws SecurityException    If a security manager, <i>s</i>, is present and any of the
     *                              following conditions is met:
     *
     *                              <ul>
     *
     *                              <li> the caller's class loader is not the same as the
     *                              class loader of this class and invocation of
     *                              {@link SecurityManager#checkPermission
     *                              s.checkPermission} method with
     *                              {@code RuntimePermission("accessDeclaredMembers")}
     *                              denies access to the declared field
     *
     *                              <li> the caller's class loader is not the same as or an
     *                              ancestor of the class loader for the current class and
     *                              invocation of {@link SecurityManager#checkPackageAccess
     *                              s.checkPackageAccess()} denies access to the package
     *                              of this class
     *
     *                              </ul>
     * @jls 8.2 Class Members
     * @jls 8.3 Field Declarations
     * @since 1.1
     */
    // 返回当前类中指定名称的字段，但不包括父类/父接口中的字段
    @CallerSensitive
    public Field getDeclaredField(String name) throws NoSuchFieldException, SecurityException {
        Objects.requireNonNull(name);
    
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true);
        }
    
        Field field = searchFields(privateGetDeclaredFields(false), name);
        if(field == null) {
            throw new NoSuchFieldException(name);
        }
    
        return getReflectionFactory().copyField(field);
    }
    
    /*▲ Field ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ Annotation ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * @since 1.5
     */
    // 1-1 返回该类上所有类型的注解，包括继承来的注解
    public Annotation[] getAnnotations() {
        return AnnotationParser.toArray(annotationData().annotations);
    }
    
    /**
     * @throws NullPointerException {@inheritDoc}
     * @since 1.5
     */
    // 1-2 返回该类上指定类型的注解，包括继承来的注解
    @SuppressWarnings("unchecked")
    public <A extends Annotation> A getAnnotation(Class<A> annotationClass) {
        Objects.requireNonNull(annotationClass);
        
        return (A) annotationData().annotations.get(annotationClass);
    }
    
    /**
     * @throws NullPointerException {@inheritDoc}
     * @since 1.8
     */
    /*
     * 1-3
     *
     * 返回该类上指定类型的注解，包括继承来的注解。[支持获取@Repeatable类型的注解]
     * 与getAnnotation()方法的区别是：
     * 1. 此方法可以处理标记为@Repeatable的注解，对于多个@Repeatable注解，将其放到一个数组中返回
     * 2. 对于非@Repeatable注解，该方法也将其放入数组中返回，但getAnnotation()方法可以直接将其返回
     */
    @Override
    public <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationClass) {
        Objects.requireNonNull(annotationClass);
        
        AnnotationData annotationData = annotationData();
        return AnnotationSupport.getAssociatedAnnotations(annotationData.declaredAnnotations, this, annotationClass);
    }
    
    /**
     * @since 1.5
     */
    // 2-1 返回该类上所有类型的注解，不包括继承来的注解
    public Annotation[] getDeclaredAnnotations() {
        return AnnotationParser.toArray(annotationData().declaredAnnotations);
    }
    
    /**
     * @throws NullPointerException {@inheritDoc}
     * @since 1.8
     */
    // 2-2 返回该类上指定类型的注解，不包括继承来的注解
    @Override
    @SuppressWarnings("unchecked")
    public <A extends Annotation> A getDeclaredAnnotation(Class<A> annotationClass) {
        Objects.requireNonNull(annotationClass);
        
        return (A) annotationData().declaredAnnotations.get(annotationClass);
    }
    
    /**
     * @throws NullPointerException {@inheritDoc}
     * @since 1.8
     */
    /*
     * 2-3
     *
     * 返回该类上指定类型的注解，不包括继承来的注解。[支持获取@Repeatable类型的注解]
     * 与getDeclaredAnnotation()方法的区别是：
     * 1. 此方法可以处理标记为@Repeatable的注解，对于多个@Repeatable注解，将其放到一个数组中返回
     * 2. 对于非@Repeatable注解，该方法也将其放入数组中返回，但getDeclaredAnnotation()方法可以直接将其返回
     */
    @Override
    public <A extends Annotation> A[] getDeclaredAnnotationsByType(Class<A> annotationClass) {
        Objects.requireNonNull(annotationClass);
        
        return AnnotationSupport.getDirectlyAndIndirectlyPresent(annotationData().declaredAnnotations, annotationClass);
    }
    
    /**
     * Returns an {@code AnnotatedType} object that represents the use of a
     * type to specify the superclass of the entity represented by this {@code
     * Class} object. (The <em>use</em> of type Foo to specify the superclass
     * in '...  extends Foo' is distinct from the <em>declaration</em> of type
     * Foo.)
     *
     * <p> If this {@code Class} object represents a type whose declaration
     * does not explicitly indicate an annotated superclass, then the return
     * value is an {@code AnnotatedType} object representing an element with no
     * annotations.
     *
     * <p> If this {@code Class} represents either the {@code Object} class, an
     * interface type, an array type, a primitive type, or void, the return
     * value is {@code null}.
     *
     * @return an object representing the superclass
     *
     * @since 1.8
     */
    /*
     * 返回"类型注解+父类"
     *
     * 示例：
     *
     * public class Child
     *     extends @注解01 @注解02 Parent
     *     implements @注解03 Interface01, @注解04 Interface02 {
     * }
     *
     * 则：
     * AnnotatedType at = Child.class.getAnnotatedSuperclass();
     * Annotation[] annotations =at.getAnnotations();
     * Type type = at.getType();
     *
     * 其中：
     * at代表“@注解01 @注解02 Parent”这个整体
     * annotations代表"@注解01"和"@注解02"这两个注解
     * type代表Parent这个类
     */
    public AnnotatedType getAnnotatedSuperclass() {
        if(this == Object.class || isInterface() || isArray() || isPrimitive() || this == Void.TYPE) {
            return null;
        }
        
        return TypeAnnotationParser.buildAnnotatedSuperclass(getRawTypeAnnotations(), getConstantPool(), this);
    }
    
    /**
     * Returns an array of {@code AnnotatedType} objects that represent the use
     * of types to specify superinterfaces of the entity represented by this
     * {@code Class} object. (The <em>use</em> of type Foo to specify a
     * superinterface in '... implements Foo' is distinct from the
     * <em>declaration</em> of type Foo.)
     *
     * <p> If this {@code Class} object represents a class, the return value is
     * an array containing objects representing the uses of interface types to
     * specify interfaces implemented by the class. The order of the objects in
     * the array corresponds to the order of the interface types used in the
     * 'implements' clause of the declaration of this {@code Class} object.
     *
     * <p> If this {@code Class} object represents an interface, the return
     * value is an array containing objects representing the uses of interface
     * types to specify interfaces directly extended by the interface. The
     * order of the objects in the array corresponds to the order of the
     * interface types used in the 'extends' clause of the declaration of this
     * {@code Class} object.
     *
     * <p> If this {@code Class} object represents a class or interface whose
     * declaration does not explicitly indicate any annotated superinterfaces,
     * the return value is an array of length 0.
     *
     * <p> If this {@code Class} object represents either the {@code Object}
     * class, an array type, a primitive type, or void, the return value is an
     * array of length 0.
     *
     * @return an array representing the superinterfaces
     *
     * @since 1.8
     */
    /*
     * 返回"类型注解+父接口"
     *
     * 示例：
     *
     * public class Child
     *     extends @注解01 @注解02 Parent
     *     implements @注解03 Interface01, @注解04 Interface02 {
     * }
     *
     * 则：
     * AnnotatedType[] ats = Child.class.getAnnotatedInterfaces();
     * for(AnnotatedType at : ats){
     *     Annotation[] annotations =at.getAnnotations();
     *     Type type = at.getType();
     * }
     *
     * 其中：
     * ats数组中包含了“@注解03 Interface01”、“@注解04 Interface02”这两个整体
     * annotations分别包含了每个整体上的注解
     * type代表每个整体中包含的接口
     */
    public AnnotatedType[] getAnnotatedInterfaces() {
        return TypeAnnotationParser.buildAnnotatedInterfaces(getRawTypeAnnotations(), getConstantPool(), this);
    }
    
    /*▲ Annotation ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ 类加载器 ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Returns the class loader for the class.  Some implementations may use
     * null to represent the bootstrap class loader. This method will return
     * null in such implementations if this class was loaded by the bootstrap
     * class loader.
     *
     * <p>If this object
     * represents a primitive type or void, null is returned.
     *
     * @return the class loader that loaded the class or interface
     * represented by this object.
     *
     * @throws SecurityException if a security manager is present, and the caller's class loader
     *                           is not {@code null} and is not the same as or an ancestor of the
     *                           class loader for the class whose class loader is requested,
     *                           and the caller does not have the
     *                           {@link RuntimePermission}{@code ("getClassLoader")}
     * @see java.lang.ClassLoader
     * @see SecurityManager#checkPermission
     * @see java.lang.RuntimePermission
     *
     */
    // 获取定义当前类的类加载器信息
    @CallerSensitive
    @ForceInline
    public ClassLoader getClassLoader() {
        // 2-1 返回该元素上所有类型的注解（对于类来说，不包括继承来的注解）
        ClassLoader cl = getClassLoader0();
        if(cl == null) {
            return null;
        }
    
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            ClassLoader.checkClassLoaderPermission(cl, Reflection.getCallerClass());
        }
    
        return cl;
    }
    
    // 返回当前类的类加载器
    ClassLoader getClassLoader0() {
        return classLoader;
    }
    
    /*▲ 类加载器 ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ 加载资源 ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Finds a resource with a given name.
     *
     * <p> If this class is in a named {@link Module Module} then this method
     * will attempt to find the resource in the module. This is done by
     * delegating to the module's class loader {@link
     * ClassLoader#findResource(String, String) findResource(String,String)}
     * method, invoking it with the module name and the absolute name of the
     * resource. Resources in named modules are subject to the rules for
     * encapsulation specified in the {@code Module} {@link
     * Module#getResourceAsStream getResourceAsStream} method and so this
     * method returns {@code null} when the resource is a
     * non-"{@code .class}" resource in a package that is not open to the
     * caller's module.
     *
     * <p> Otherwise, if this class is not in a named module then the rules for
     * searching resources associated with a given class are implemented by the
     * defining {@linkplain ClassLoader class loader} of the class.  This method
     * delegates to this object's class loader. If this object was loaded by
     * the bootstrap class loader, the method delegates to {@link
     * ClassLoader#getSystemResource}.
     *
     * <p> Before delegation, an absolute resource name is constructed from the
     * given resource name using this algorithm:
     *
     * <ul>
     *
     * <li> If the {@code name} begins with a {@code '/'}
     * (<code>'&#92;u002f'</code>), then the absolute name of the resource is the
     * portion of the {@code name} following the {@code '/'}.
     *
     * <li> Otherwise, the absolute name is of the following form:
     *
     * <blockquote>
     * {@code modified_package_name/name}
     * </blockquote>
     *
     * <p> Where the {@code modified_package_name} is the package name of this
     * object with {@code '/'} substituted for {@code '.'}
     * (<code>'&#92;u002e'</code>).
     *
     * </ul>
     *
     * @param resName name of the desired resource
     *
     * @return A {@link java.net.URL} object; {@code null} if no resource with
     * this name is found, the resource cannot be located by a URL, the
     * resource is in a package that is not
     * {@linkplain Module#isOpen(String, Module) open} to at least the caller
     * module, or access to the resource is denied by the security
     * manager.
     *
     * @throws NullPointerException If {@code name} is {@code null}
     * @revised 9
     * @spec JPMS
     * @since 1.1
     */
    /*
     * 查找指定名称的资源，并返回其URL。
     * 如果当前类位于命名模块，则在模块路径(根目录)下查找；否则，在类路径(根目录)上查找。
     *
     * resName路径需以"/"分割。
     * 如果resName以'/'开头，则会在模块路径/类路径的根目录下查找；
     * 如果resName不以'/'开头，则会在(当前类所在目录+"/"+resName)下查找
     */
    @CallerSensitive
    public URL getResource(String resName) {
    
        // 如果resName以'/'开头，则去掉开头的"/"后返回；否则，将当前类所在包名转换为路径，并将该路径添加到resName前面后返回
        resName = resolveName(resName);
    
        // 获取当前类所在的module
        Module thisModule = getModule();
    
        // 如果thisModule是命名模块
        if(thisModule.isNamed()) {
            // check if resource can be located by caller
            if(Resources.canEncapsulate(resName) && !isOpenToCaller(resName, Reflection.getCallerClass())) {
                return null;
            }
    
            // resource not encapsulated or in package open to caller
            String moduleName = thisModule.getName();
    
            // 获取当前类的类加载器
            ClassLoader loader = getClassLoader0();
    
            // 在模块moduleName下查找名称为resName的资源
            try {
                if(loader == null) {
                    // 在指定的模块路径或bootstrap类加载器的类路径下查找匹配的资源
                    return BootLoader.findResource(moduleName, resName);
                } else {
                    // 在指定的模块路径或loader类加载器的类路径下查找匹配的资源
                    return loader.findResource(moduleName, resName);
                }
            } catch(IOException ioe) {
                return null;
            }
        }
    
        // 如果当前类是未命名模块，则尝试用类加载器直接加载资源
        ClassLoader loader = getClassLoader0();
    
        if(loader == null) {
            // 自顶向下加载资源，截止到system类加载器。返回【首个】匹配到的资源的URL
            return ClassLoader.getSystemResource(resName);
        } else {
            // 自顶向下加载资源，截止到类加载器loader。返回【首个】匹配到的资源的URL
            return loader.getResource(resName);
        }
    }
    
    /**
     * Finds a resource with a given name.
     *
     * <p> If this class is in a named {@link Module Module} then this method
     * will attempt to find the resource in the module. This is done by
     * delegating to the module's class loader {@link
     * ClassLoader#findResource(String, String) findResource(String,String)}
     * method, invoking it with the module name and the absolute name of the
     * resource. Resources in named modules are subject to the rules for
     * encapsulation specified in the {@code Module} {@link
     * Module#getResourceAsStream getResourceAsStream} method and so this
     * method returns {@code null} when the resource is a
     * non-"{@code .class}" resource in a package that is not open to the
     * caller's module.
     *
     * <p> Otherwise, if this class is not in a named module then the rules for
     * searching resources associated with a given class are implemented by the
     * defining {@linkplain ClassLoader class loader} of the class.  This method
     * delegates to this object's class loader.  If this object was loaded by
     * the bootstrap class loader, the method delegates to {@link
     * ClassLoader#getSystemResourceAsStream}.
     *
     * <p> Before delegation, an absolute resource name is constructed from the
     * given resource name using this algorithm:
     *
     * <ul>
     *
     * <li> If the {@code name} begins with a {@code '/'}
     * (<code>'&#92;u002f'</code>), then the absolute name of the resource is the
     * portion of the {@code name} following the {@code '/'}.
     *
     * <li> Otherwise, the absolute name is of the following form:
     *
     * <blockquote>
     * {@code modified_package_name/name}
     * </blockquote>
     *
     * <p> Where the {@code modified_package_name} is the package name of this
     * object with {@code '/'} substituted for {@code '.'}
     * (<code>'&#92;u002e'</code>).
     *
     * </ul>
     *
     * @param resName name of the desired resource
     *
     * @return A {@link java.io.InputStream} object; {@code null} if no
     * resource with this name is found, the resource is in a package
     * that is not {@linkplain Module#isOpen(String, Module) open} to at
     * least the caller module, or access to the resource is denied
     * by the security manager.
     *
     * @throws NullPointerException If {@code name} is {@code null}
     * @revised 9
     * @spec JPMS
     * @see Module#getResourceAsStream(String)
     * @since 1.1
     */
    /*
     * 查找指定名称的资源，并返回其输入流。
     * 如果当前类位于命名模块，则在模块路径(根目录)下查找；否则，在类路径(根目录)上查找。
     *
     * resName路径内部需以"/"分割。
     * 如果resName以'/'开头，则会在模块路径/类路径的根目录下查找；
     * 如果resName不以'/'开头，则会在(当前类所在目录+"/"+resName)下查找
     */
    @CallerSensitive
    public InputStream getResourceAsStream(String resName) {
    
        // 如果resName以'/'开头，则去掉开头的"/"后返回；否则，将当前类所在包名转换为路径，并将该路径添加到resName前面后返回
        resName = resolveName(resName);
    
        // 获取当前类所在的module
        Module thisModule = getModule();
    
        // 如果thisModule是命名模块
        if(thisModule.isNamed()) {
            // check if resource can be located by caller
            if(Resources.canEncapsulate(resName) && !isOpenToCaller(resName, Reflection.getCallerClass())) {
                return null;
            }
    
            // resource not encapsulated or in package open to caller
            String mn = thisModule.getName();
    
            // 获取当前类的类加载器
            ClassLoader loader = getClassLoader0();
    
            try {
        
                // special-case built-in class loaders to avoid the need for a URL connection
                if(loader == null) {
                    // 在指定的模块路径(根目录)或bootstrap类加载器关联的类路径(根目录)下查找匹配的资源
                    return BootLoader.findResourceAsStream(mn, resName);
                } else if(loader instanceof BuiltinClassLoader) {
                    // 在指定的模块路径(根目录)或类加载器loader关联的类路径(根目录)下查找匹配的资源
                    return ((BuiltinClassLoader) loader).findResourceAsStream(mn, resName);
                } else {
                    // 在指定的模块路径或类加载器loader的类路径下查找匹配的资源
                    URL url = loader.findResource(mn, resName);
            
                    // 打开指定url处的流
                    return (url != null) ? url.openStream() : null;
                }
        
            } catch(IOException | SecurityException e) {
                return null;
            }
        }
    
        // 如果当前类是未命名模块，则尝试用类加载器直接加载资源
        ClassLoader loader = getClassLoader0();
    
        if(loader == null) {
            // 自顶向下加载资源，截止到system类加载器。返回【首个】匹配到的资源的输入流
            return ClassLoader.getSystemResourceAsStream(resName);
        } else {
            // 自顶向下加载资源，截止到类加载器loader。返回【首个】匹配到的资源的流
            return loader.getResourceAsStream(resName);
        }
    }
    
    /*▲ 加载资源 ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ 其他 ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Returns the elements of this enum class or null if this
     * Class object does not represent an enum type.
     *
     * @return an array containing the values comprising the enum class
     * represented by this Class object in the order they're
     * declared, or null if this Class object does not
     * represent an enum type
     *
     * @since 1.5
     */
    // 如果当前类是枚举类，则返回其包含的枚举常量
    public T[] getEnumConstants() {
        T[] values = getEnumConstantsShared();
        return (values != null) ? values.clone() : null;
    }
    
    /**
     * Gets the package of this class.
     *
     * <p>If this class represents an array type, a primitive type or void,
     * this method returns {@code null}.
     *
     * @return the package of this class.
     *
     * @revised 9
     * @spec JPMS
     */
    // 获取当前类所在的包的Package信息
    public Package getPackage() {
        if(isPrimitive() || isArray()) {
            return null;
        }
    
        ClassLoader cl = getClassLoader0();
        
        return cl != null
            ? cl.definePackage(this)
            : BootLoader.definePackage(this);
    }
    
    /**
     * Returns the fully qualified package name.
     *
     * <p> If this class is a top level class, then this method returns the fully
     * qualified name of the package that the class is a member of, or the
     * empty string if the class is in an unnamed package.
     *
     * <p> If this class is a member class, then this method is equivalent to
     * invoking {@code getPackageName()} on the {@linkplain #getEnclosingClass
     * enclosing class}.
     *
     * <p> If this class is a {@linkplain #isLocalClass local class} or an {@linkplain
     * #isAnonymousClass() anonymous class}, then this method is equivalent to
     * invoking {@code getPackageName()} on the {@linkplain #getDeclaringClass
     * declaring class} of the {@linkplain #getEnclosingMethod enclosing method} or
     * {@linkplain #getEnclosingConstructor enclosing constructor}.
     *
     * <p> If this class represents an array type then this method returns the
     * package name of the element type. If this class represents a primitive
     * type or void then the package name "{@code java.lang}" is returned.
     *
     * @return the fully qualified package name
     *
     * @spec JPMS
     * @jls 6.7  Fully Qualified Names
     * @since 9
     */
    // 获取Package名称
    public String getPackageName() {
        String pn = this.packageName;
        if(pn != null) {
            return pn;
        }
    
        Class<?> c = this;
        while(c.isArray()) {
            c = c.getComponentType();
        }
    
        if(c.isPrimitive()) {
            pn = "java.lang";
        } else {
            String cn = c.getName();
            int dot = cn.lastIndexOf('.');
            pn = (dot != -1) ? cn.substring(0, dot).intern() : "";
        }
    
        this.packageName = pn;
    
        return pn;
    }
    
    /**
     * Returns the module that this class or interface is a member of.
     *
     * If this class represents an array type then this method returns the
     * {@code Module} for the element type. If this class represents a
     * primitive type or void, then the {@code Module} object for the
     * {@code java.base} module is returned.
     *
     * If this class is in an unnamed module then the {@linkplain
     * ClassLoader#getUnnamedModule() unnamed} {@code Module} of the class
     * loader for this class is returned.
     *
     * @return the module that this class or interface is a member of
     *
     * @spec JPMS
     * @since 9
     */
    // 获取Module信息
    public Module getModule() {
        return module;
    }
    
    /**
     * Returns the Java language modifiers for this class or interface, encoded
     * in an integer. The modifiers consist of the Java Virtual Machine's
     * constants for {@code public}, {@code protected},
     * {@code private}, {@code final}, {@code static},
     * {@code abstract} and {@code interface}; they should be decoded
     * using the methods of class {@code Modifier}.
     *
     * <p> If the underlying class is an array class, then its
     * {@code public}, {@code private} and {@code protected}
     * modifiers are the same as those of its component type.  If this
     * {@code Class} represents a primitive type or void, its
     * {@code public} modifier is always {@code true}, and its
     * {@code protected} and {@code private} modifiers are always
     * {@code false}. If this object represents an array class, a
     * primitive type or void, then its {@code final} modifier is always
     * {@code true} and its interface modifier is always
     * {@code false}. The values of its other modifiers are not determined
     * by this specification.
     *
     * <p> The modifier encodings are defined in <em>The Java Virtual Machine
     * Specification</em>, table 4.1.
     *
     * @return the {@code int} representing the modifiers for this class
     *
     * @see java.lang.reflect.Modifier
     * @since 1.1
     */
    // 获取类的修饰符信息，参见java.lang.reflect.Modifier
    @HotSpotIntrinsicCandidate
    public native int getModifiers();
    
    /**
     * Gets the signers of this class.
     *
     * @return the signers of this class, or null if there are no signers.
     * In particular, this method returns null if this object represents a primitive type or void.
     *
     * @since 1.1
     */
    // 获取签名信息
    public native Object[] getSigners();
    
    /**
     * Returns the {@code ProtectionDomain} of this class.  If there is a
     * security manager installed, this method first calls the security
     * manager's {@code checkPermission} method with a
     * {@code RuntimePermission("getProtectionDomain")} permission to
     * ensure it's ok to get the
     * {@code ProtectionDomain}.
     *
     * @return the ProtectionDomain of this class
     *
     * @throws SecurityException if a security manager exists and its
     *                           {@code checkPermission} method doesn't allow
     *                           getting the ProtectionDomain.
     * @see java.security.ProtectionDomain
     * @see SecurityManager#checkPermission
     * @see java.lang.RuntimePermission
     * @since 1.2
     */
    public ProtectionDomain getProtectionDomain() {
        SecurityManager sm = System.getSecurityManager();
        if(sm != null) {
            sm.checkPermission(SecurityConstants.GET_PD_PERMISSION);
        }
    
        ProtectionDomain pd = getProtectionDomain0();
        if(pd != null) {
            return pd;
        }
    
        if(allPermDomain == null) {
            java.security.Permissions perms = new java.security.Permissions();
            perms.add(SecurityConstants.ALL_PERMISSION);
            allPermDomain = new java.security.ProtectionDomain(null, perms);
        }
    
        pd = allPermDomain;
    
        return pd;
    }
    
    /**
     * Returns the assertion status that would be assigned to this
     * class if it were to be initialized at the time this method is invoked.
     * If this class has had its assertion status set, the most recent
     * setting will be returned; otherwise, if any package default assertion
     * status pertains to this class, the most recent setting for the most
     * specific pertinent package default assertion status is returned;
     * otherwise, if this class is not a system class (i.e., it has a
     * class loader) its class loader's default assertion status is returned;
     * otherwise, the system class default assertion status is returned.
     * <p>
     * Few programmers will have any need for this method; it is provided
     * for the benefit of the JRE itself.  (It allows a class to determine at
     * the time that it is initialized whether assertions should be enabled.)
     * Note that this method is not guaranteed to return the actual
     * assertion status that was (or will be) associated with the specified
     * class when it was (or will be) initialized.
     *
     * @return the desired assertion status of the specified class.
     *
     * @see java.lang.ClassLoader#setClassAssertionStatus
     * @see java.lang.ClassLoader#setPackageAssertionStatus
     * @see java.lang.ClassLoader#setDefaultAssertionStatus
     * @since 1.4
     */
    public boolean desiredAssertionStatus() {
        ClassLoader loader = getClassLoader0();
        // If the loader is null this is a system class, so ask the VM
        if(loader == null) {
            return desiredAssertionStatus0(this);
        }
        
        // If the classloader has been initialized with the assertion
        // directives, ask it. Otherwise, ask the VM.
        synchronized(loader.assertionLock) {
            if(loader.classAssertionStatus != null) {
                return loader.desiredAssertionStatus(getName());
            }
        }
    
        return desiredAssertionStatus0(this);
    }
    
    /*▲ 其他 ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ 转换 ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Casts an object to the class or interface represented by this {@code Class} object.
     *
     * @param obj the object to be cast
     *
     * @return the object after casting, or null if obj is null
     *
     * @throws ClassCastException if the object is not
     *                            null and is not assignable to the type T.
     * @since 1.5
     */
    // 将非空的obj转换为该类型代表的类或接口（要保证兼容性）
    @SuppressWarnings("unchecked")
    @HotSpotIntrinsicCandidate
    public T cast(Object obj) {
        if(obj != null && !isInstance(obj)) {
            throw new ClassCastException(cannotCastMsg(obj));
        }
        return (T) obj;
    }
    
    /**
     * Casts this {@code Class} object to represent a subclass of the class
     * represented by the specified class object.  Checks that the cast
     * is valid, and throws a {@code ClassCastException} if it is not.  If
     * this method succeeds, it always returns a reference to this class object.
     *
     * <p>This method is useful when a client needs to "narrow" the type of
     * a {@code Class} object to pass it to an API that restricts the
     * {@code Class} objects that it is willing to accept.  A cast would
     * generate a compile-time warning, as the correctness of the cast
     * could not be checked at runtime (because generic types are implemented
     * by erasure).
     *
     * @param <U>   the type to cast this class object to
     * @param clazz the class of the type to cast this class object to
     *
     * @return this {@code Class} object, cast to represent a subclass of
     * the specified class object.
     *
     * @throws ClassCastException if this {@code Class} object does not
     *                            represent a subclass of the specified class (here "subclass" includes
     *                            the class itself).
     * @since 1.5
     */
    // 如果clazz类型是当前类的父类/父接口，则返回父类型
    @SuppressWarnings("unchecked")
    public <U> Class<? extends U> asSubclass(Class<U> clazz) {
        // 如果当前类型的对象不是clazz类型的实例，则会抛异常
        if(!clazz.isAssignableFrom(this)) {
            throw new ClassCastException(this.toString());
        }
    
        return (Class<? extends U>) this;
    }
    
    /*▲ 转换 ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    
    /*▼ 字符串化 ████████████████████████████████████████████████████████████████████████████████┓ */
    
    /**
     * Converts the object to a string. The string representation is the
     * string "class" or "interface", followed by a space, and then by the
     * fully qualified name of the class in the format returned by
     * {@code getName}.  If this {@code Class} object represents a
     * primitive type, this method returns the name of the primitive type.  If
     * this {@code Class} object represents void this method returns
     * "void". If this {@code Class} object represents an array type,
     * this method returns "class " followed by {@code getName}.
     *
     * @return a string representation of this class object.
     */
    public String toString() {
        return (isInterface() ? "interface " : (isPrimitive() ? "" : "class ")) + getName();
    }
    
    /**
     * Returns a string describing this {@code Class}, including
     * information about modifiers and type parameters.
     *
     * The string is formatted as a list of type modifiers, if any,
     * followed by the kind of type (empty string for primitive types
     * and {@code class}, {@code enum}, {@code interface}, or
     * <code>&#64;</code>{@code interface}, as appropriate), followed
     * by the type's name, followed by an angle-bracketed
     * comma-separated list of the type's type parameters, if any.
     *
     * A space is used to separate modifiers from one another and to
     * separate any modifiers from the kind of type. The modifiers
     * occur in canonical order. If there are no type parameters, the
     * type parameter list is elided.
     *
     * For an array type, the string starts with the type name,
     * followed by an angle-bracketed comma-separated list of the
     * type's type parameters, if any, followed by a sequence of
     * {@code []} characters, one set of brackets per dimension of
     * the array.
     *
     * <p>Note that since information about the runtime representation
     * of a type is being generated, modifiers not present on the
     * originating source code or illegal on the originating source
     * code may be present.
     *
     * @return a string describing this {@code Class}, including
     * information about modifiers and type parameters
     *
     * @since 1.8
     */
    // 打印类完整声明
    public String toGenericString() {
        if(isPrimitive()) {
            return toString();
        }
    
        StringBuilder sb = new StringBuilder();
        Class<?> component = this;
        int arrayDepth = 0;
    
        if(isArray()) {
            do {
                arrayDepth++;
                component = component.getComponentType();
            } while(component.isArray());
            sb.append(component.getName());
        } else {
            // Class modifiers are a superset of interface modifiers
            int modifiers = getModifiers() & Modifier.classModifiers();
            if(modifiers != 0) {
                sb.append(Modifier.toString(modifiers));
                sb.append(' ');
            }
        
            if(isAnnotation()) {
                sb.append('@');
            }
        
            if(isInterface()) { // Note: all annotation types are interfaces
                sb.append("interface");
            } else {
                if(isEnum())
                    sb.append("enum");
                else
                    sb.append("class");
            }
            sb.append(' ');
            sb.append(getName());
        }
    
        TypeVariable<?>[] typeparms = component.getTypeParameters();
        if(typeparms.length>0) {
            StringJoiner sj = new StringJoiner(",", "<", ">");
            for(TypeVariable<?> typeparm : typeparms) {
                sj.add(typeparm.getTypeName());
            }
            sb.append(sj.toString());
        }
    
        for(int i = 0; i<arrayDepth; i++) {
            sb.append("[]");
        }
    
        return sb.toString();
    }
    
    /*▲ 字符串化 ████████████████████████████████████████████████████████████████████████████████┛ */
    
    
    /** Called after security check for system loader access checks have been made. */
    private static native Class<?> forName0(String className, boolean initialize, ClassLoader loader, Class<?> caller) throws ClassNotFoundException;
    
    /**
     * Return the Virtual Machine's Class object for the named
     * primitive type.
     */
    static native Class<?> getPrimitiveClass(String name);
    
    static byte[] getExecutableTypeAnnotationBytes(Executable ex) {
        return getReflectionFactory().getExecutableTypeAnnotationBytes(ex);
    }
    
    /**
     * Returns the elements of this enum class or null if this Class object does not represent an enum type;
     * identical to getEnumConstants except that the result is uncloned, cached, and shared by all callers.
     */
    T[] getEnumConstantsShared() {
        T[] constants = enumConstants;
        
        if(constants == null) {
            if(!isEnum()) {
                return null;
            }
            
            try {
                final Method values = getMethod("values");
                
                AccessController.doPrivileged(new PrivilegedAction<>() {
                    public Void run() {
                        values.setAccessible(true);
                        return null;
                    }
                });
                
                @SuppressWarnings("unchecked")
                T[] temporaryConstants = (T[]) values.invoke(null);
                
                enumConstants = constants = temporaryConstants;
                
                // These can happen when users concoct enum-like classes that don't comply with the enum spec.
            } catch(InvocationTargetException | NoSuchMethodException | IllegalAccessException ex) {
                return null;
            }
        }
        
        return constants;
    }
    
    /**
     * Returns the list of {@code Method} objects for the declared public
     * methods of this class or interface that have the specified method name
     * and parameter types.
     *
     * @param name           the name of the method
     * @param parameterTypes the parameter array
     *
     * @return the list of {@code Method} objects for the public methods of
     * this class matching the specified name and parameters
     */
    List<Method> getDeclaredPublicMethods(String name, Class<?>... parameterTypes) {
        Method[] methods = privateGetDeclaredMethods(/* publicOnly */ true);
        ReflectionFactory factory = getReflectionFactory();
        List<Method> result = new ArrayList<>();
        for(Method method : methods) {
            if(method.getName().equals(name) && Arrays.equals(factory.getExecutableSharedParameterTypes(method), parameterTypes)) {
                result.add(factory.copyMethod(method));
            }
        }
        return result;
    }
    
    /**
     * Set the signers of this class.
     */
    // 为当前类设置签名信息
    native void setSigners(Object[] signers);
    
    // Annotations handling
    native byte[] getRawAnnotations();
    
    // Since 1.8
    native byte[] getRawTypeAnnotations();
    
    native ConstantPool getConstantPool();
    
    /**
     * Returns a map from simple name to enum constant.  This package-private
     * method is used internally by Enum to implement
     * {@code public static <T extends Enum<T>> T valueOf(Class<T>, String)}
     * efficiently.  Note that the map is returned by this method is
     * created lazily on first use.  Typically it won't ever get created.
     */
    Map<String, T> enumConstantDirectory() {
        Map<String, T> directory = enumConstantDirectory;
        if(directory != null) {
            return directory;
        }
    
        T[] universe = getEnumConstantsShared();
    
        if(universe == null) {
            throw new IllegalArgumentException(getName() + " is not an enum type");
        }
    
        directory = new HashMap<>((int) (universe.length / 0.75f) + 1);
    
        for(T constant : universe) {
            directory.put(((Enum<?>) constant).name(), constant);
        }
    
        enumConstantDirectory = directory;
    
        return directory;
    }
    
    boolean casAnnotationType(AnnotationType oldType, AnnotationType newType) {
        return Atomic.casAnnotationType(this, oldType, newType);
    }
    
    AnnotationType getAnnotationType() {
        return annotationType;
    }
    
    Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap() {
        return annotationData().declaredAnnotations;
    }
    
    private static Class<?> toClass(Type o) {
        if(o instanceof GenericArrayType)
            return Array.newInstance(toClass(((GenericArrayType) o).getGenericComponentType()), 0).getClass();
        return (Class<?>) o;
    }
    
    private static void addAll(Collection<Field> c, Field[] o) {
        Collections.addAll(c, o);
    }
    
    // This method does not copy the returned Field object!
    private static Field searchFields(Field[] fields, String name) {
        for(Field field : fields) {
            if(field.getName().equals(name)) {
                return field;
            }
        }
    
        return null;
    }
    
    // This method does not copy the returned Method object!
    private static Method searchMethods(Method[] methods, String name, Class<?>[] parameterTypes) {
        ReflectionFactory fact = getReflectionFactory();
        Method res = null;
        for(Method m : methods) {
            if(m.getName().equals(name) && arrayContentsEq(parameterTypes, fact.getExecutableSharedParameterTypes(m)) && (res == null || (res.getReturnType() != m.getReturnType() && res.getReturnType().isAssignableFrom(m.getReturnType())))) {
                res = m;
            }
        }
        return res;
    }
    
    private static boolean arrayContentsEq(Object[] a1, Object[] a2) {
        if(a1 == null) {
            return a2 == null || a2.length == 0;
        }
        
        if(a2 == null) {
            return a1.length == 0;
        }
        
        if(a1.length != a2.length) {
            return false;
        }
        
        for(int i = 0; i<a1.length; i++) {
            if(a1[i] != a2[i]) {
                return false;
            }
        }
        
        return true;
    }
    
    private static Field[] copyFields(Field[] arg) {
        Field[] out = new Field[arg.length];
        ReflectionFactory fact = getReflectionFactory();
        for(int i = 0; i<arg.length; i++) {
            out[i] = fact.copyField(arg[i]);
        }
        return out;
    }
    
    private static Method[] copyMethods(Method[] arg) {
        Method[] out = new Method[arg.length];
        ReflectionFactory fact = getReflectionFactory();
        for(int i = 0; i<arg.length; i++) {
            out[i] = fact.copyMethod(arg[i]);
        }
        return out;
    }
    
    private static <U> Constructor<U>[] copyConstructors(Constructor<U>[] arg) {
        Constructor<U>[] out = arg.clone();
        ReflectionFactory fact = getReflectionFactory();
        for(int i = 0; i<out.length; i++) {
            out[i] = fact.copyConstructor(out[i]);
        }
        return out;
    }
    
    // Retrieves the desired assertion status of this class from the VM
    private static native boolean desiredAssertionStatus0(Class<?> clazz);
    
    // Fetches the factory for reflective objects
    private static ReflectionFactory getReflectionFactory() {
        if(reflectionFactory == null) {
            reflectionFactory = java.security.AccessController.doPrivileged(new ReflectionFactory.GetReflectionFactoryAction());
        }
        return reflectionFactory;
    }
    
    private static native void registerNatives();
    
    private native String getName0();
    
    private Class<?>[] getInterfaces(boolean cloneArray) {
        ReflectionData<T> rd = reflectionData();
        if(rd == null) {
            // no cloning required
            return getInterfaces0();
        }
    
        Class<?>[] interfaces = rd.interfaces;
        if(interfaces == null) {
            interfaces = getInterfaces0();
            rd.interfaces = interfaces;
        }
    
        // defensively copy if requested
        return cloneArray ? interfaces.clone() : interfaces;
    }
    
    private native Class<?>[] getInterfaces0();
    
    private native Object[] getEnclosingMethod0();
    
    private EnclosingMethodInfo getEnclosingMethodInfo() {
        Object[] enclosingInfo = getEnclosingMethod0();
        if(enclosingInfo == null) {
            return null;
        }
    
        return new EnclosingMethodInfo(enclosingInfo);
    }
    
    private native Class<?> getDeclaringClass0();
    
    private String getSimpleName0() {
        if(isArray()) {
            return getComponentType().getSimpleName() + "[]";
        }
    
        String simpleName = getSimpleBinaryName();
    
        if(simpleName == null) { // top level class
            simpleName = getName();
            simpleName = simpleName.substring(simpleName.lastIndexOf('.') + 1); // strip the package name
        }
    
        return simpleName;
    }
    
    private String getCanonicalName0() {
        if(isArray()) {
            String canonicalName = getComponentType().getCanonicalName();
            if(canonicalName != null) {
                return canonicalName + "[]";
            } else {
                return ReflectionData.NULL_SENTINEL;
            }
        }
    
        if(isLocalOrAnonymousClass()) {
            return ReflectionData.NULL_SENTINEL;
        }
    
        Class<?> enclosingClass = getEnclosingClass();
        if(enclosingClass == null) { // top level class
            return getName();
        }
        String enclosingName = enclosingClass.getCanonicalName();
        if(enclosingName == null) {
            return ReflectionData.NULL_SENTINEL;
        }
    
        return enclosingName + "." + getSimpleName();
    }
    
    /**
     * Returns the "simple binary name" of the underlying class, i.e.,
     * the binary name without the leading enclosing class name.
     * Returns {@code null} if the underlying class is a top level
     * class.
     */
    private String getSimpleBinaryName() {
        if(isTopLevelClass()) {
            return null;
        }
    
        String name = getSimpleBinaryName0();
        if(name == null) {
            return "";  // anonymous class
        }
    
        return name;
    }
    
    private native String getSimpleBinaryName0();
    
    /**
     * Returns {@code true} if this is a top level class.  Returns {@code false}
     * otherwise.
     */
    private boolean isTopLevelClass() {
        return !isLocalOrAnonymousClass() && getDeclaringClass0() == null;
    }
    
    /**
     * Returns {@code true} if this is a local class or an anonymous
     * class.  Returns {@code false} otherwise.
     */
    private boolean isLocalOrAnonymousClass() {
        // JVM Spec 4.7.7: A class must have an EnclosingMethod attribute if and only if it is a local class or an anonymous class.
        return hasEnclosingMethodInfo();
    }
    
    /**
     * Returns true if a resource with the given name can be located by the given caller.
     * All resources in a module can be located by code in the module.
     * For other callers, then the package needs to be open to the caller.
     */
    // 如果资源位于当前类所在模块下，则需要检测caller对该资源的可访问性
    private boolean isOpenToCaller(String name, Class<?> caller) {
        // assert getModule().isNamed();
        Module thisModule = getModule();
        Module callerModule = (caller != null) ? caller.getModule() : null;
    
        // 同一个模块
        if(callerModule == thisModule) {
            return true;
        }
    
        // 获取指定名称的资源所在的包
        String pn = Resources.toPackageName(name);
        if(!thisModule.getDescriptor().packages().contains(pn)) {
            return true;
        }
    
        if(callerModule == null && !thisModule.isOpen(pn)) {
            // no caller, package not open
            return false;
        }
    
        if(!thisModule.isOpen(pn, callerModule)) {
            // package not open to caller
            return false;
        }
    
        return true;
    }
    
    private boolean hasEnclosingMethodInfo() {
        Object[] enclosingInfo = getEnclosingMethod0();
        if(enclosingInfo != null) {
            EnclosingMethodInfo.validate(enclosingInfo);
            return true;
        }
        return false;
    }
    
    /**
     * Returns the ProtectionDomain of this class.
     */
    private native ProtectionDomain getProtectionDomain0();
    
    /**
     * Check if client is allowed to access members.  If access is denied,
     * throw a SecurityException.
     *
     * This method also enforces package access.
     *
     * <p> Default policy: allow all clients access with normal Java access
     * control.
     *
     * <p> NOTE: should only be called if a SecurityManager is installed
     */
    private void checkMemberAccess(SecurityManager sm, int which, Class<?> caller, boolean checkProxyInterfaces) {
        /*
         * Default policy allows access to all {@link Member#PUBLIC} members,
         * as well as access to classes that have the same class loader as the caller.
         * In all other cases, it requires RuntimePermission("accessDeclaredMembers") permission.
         */
        final ClassLoader ccl = ClassLoader.getClassLoader(caller);
        if(which != Member.PUBLIC) {
            final ClassLoader cl = getClassLoader0();
            if(ccl != cl) {
                sm.checkPermission(SecurityConstants.CHECK_MEMBER_ACCESS_PERMISSION);
            }
        }
    
        this.checkPackageAccess(sm, ccl, checkProxyInterfaces);
    }
    
    /**
     * Checks if a client loaded in ClassLoader ccl is allowed to access this
     * class under the current package access policy. If access is denied,
     * throw a SecurityException.
     *
     * NOTE: this method should only be called if a SecurityManager is active
     */
    private void checkPackageAccess(SecurityManager sm, final ClassLoader ccl, boolean checkProxyInterfaces) {
        final ClassLoader cl = getClassLoader0();
        
        if(ReflectUtil.needsPackageAccessCheck(ccl, cl)) {
            String pkg = this.getPackageName();
            if(pkg != null && !pkg.isEmpty()) {
                // skip the package access check on a proxy class in default proxy package
                if(!Proxy.isProxyClass(this) || ReflectUtil.isNonPublicProxyClass(this)) {
                    sm.checkPackageAccess(pkg);
                }
            }
        }
    
        // check package access on the proxy interfaces
        if(checkProxyInterfaces && Proxy.isProxyClass(this)) {
            ReflectUtil.checkProxyPackageAccess(ccl, this.getInterfaces());
        }
    }
    
    /**
     * Add a package name prefix if the resName is not absolute Remove leading "/" if name is absolute
     */
    // 如果resName以'/'开头，则去掉开头的"/"后返回；否则，将当前类所在包名转换为路径，并将该路径添加到resName前面后返回
    private String resolveName(String resName) {
        if(resName.startsWith("/")) {
            // 去掉绝对路径前面的"/"
            resName = resName.substring(1);
        } else {
            Class<?> c = this;
            while(c.isArray()) {
                // 获取数组的组件类型
                c = c.getComponentType();
            }
            
            // 获取当前类的包名
            String baseName = c.getPackageName();
            if(baseName != null && !baseName.isEmpty()) {
                // 将包名替换为路径名，并在其后添加资源名
                resName = baseName.replace('.', '/') + "/" + resName;
            }
        }
        
        return resName;
    }
    
    /** Lazily create and cache ReflectionData */
    private ReflectionData<T> reflectionData() {
        SoftReference<ReflectionData<T>> reflectionData = this.reflectionData;
        int classRedefinedCount = this.classRedefinedCount;
        ReflectionData<T> rd;
        if(reflectionData != null && (rd = reflectionData.get()) != null && rd.redefinedCount == classRedefinedCount) {
            return rd;
        }
    
        // else no SoftReference or cleared SoftReference or stale ReflectionData
        // -> create and replace new instance
        return newReflectionData(reflectionData, classRedefinedCount);
    }
    
    private ReflectionData<T> newReflectionData(SoftReference<ReflectionData<T>> oldReflectionData, int classRedefinedCount) {
        while(true) {
            ReflectionData<T> rd = new ReflectionData<>(classRedefinedCount);
            // try to CAS it...
            if(Atomic.casReflectionData(this, oldReflectionData, new SoftReference<>(rd))) {
                return rd;
            }
    
            // else retry
            oldReflectionData = this.reflectionData;
            classRedefinedCount = this.classRedefinedCount;
            if(oldReflectionData != null && (rd = oldReflectionData.get()) != null && rd.redefinedCount == classRedefinedCount) {
                return rd;
            }
        }
    }
    
    /** Generic signature handling */
    private native String getGenericSignature0();
    
    /** accessor for factory */
    private GenericsFactory getFactory() {
        // create scope and factory
        return CoreReflectionFactory.make(this, ClassScope.make(this));
    }
    
    /** accessor for generic info repository; generic info is lazily initialized */
    private ClassRepository getGenericInfo() {
        ClassRepository genericInfo = this.genericInfo;
    
        if(genericInfo == null) {
            String signature = getGenericSignature0();
            if(signature == null) {
                genericInfo = ClassRepository.NONE;
            } else {
                genericInfo = ClassRepository.make(signature, getFactory());
            }
            this.genericInfo = genericInfo;
        }
    
        return (genericInfo != ClassRepository.NONE) ? genericInfo : null;
    }
    
    /**
     * Returns an array of "root" fields.
     * These Field objects must NOT be propagated to the outside world, but must instead be copied via ReflectionFactory.copyField.
     */
    private Field[] privateGetDeclaredFields(boolean publicOnly) {
        Field[] res;
        ReflectionData<T> rd = reflectionData();
        if(rd != null) {
            res = publicOnly ? rd.declaredPublicFields : rd.declaredFields;
            if(res != null) {
                return res;
            }
        }
    
        // No cached value available; request value from VM
        res = Reflection.filterFields(this, getDeclaredFields0(publicOnly));
        if(rd != null) {
            if(publicOnly) {
                rd.declaredPublicFields = res;
            } else {
                rd.declaredFields = res;
            }
        }
    
        return res;
    }
    
    /**
     * Returns an array of "root" fields.
     * These Field objects must NOT be propagated to the outside world, but must instead be copied via ReflectionFactory.copyField.
     */
    private Field[] privateGetPublicFields() {
        Field[] res;
        ReflectionData<T> rd = reflectionData();
        if(rd != null) {
            res = rd.publicFields;
            if(res != null) {
                return res;
            }
        }
        
        // Use a linked hash set to ensure order is preserved and
        // fields from common super interfaces are not duplicated
        LinkedHashSet<Field> fields = new LinkedHashSet<>();
        
        // Local fields
        addAll(fields, privateGetDeclaredFields(true));
        
        // Direct superinterfaces, recursively
        for(Class<?> si : getInterfaces()) {
            addAll(fields, si.privateGetPublicFields());
        }
        
        // Direct superclass, recursively
        Class<?> sc = getSuperclass();
        if(sc != null) {
            addAll(fields, sc.privateGetPublicFields());
        }
        
        res = fields.toArray(new Field[0]);
        if(rd != null) {
            rd.publicFields = res;
        }
    
        return res;
    }
    
    /**
     * Returns an array of "root" constructors.
     * These Constructor objects must NOT be propagated to the outside world, but must instead be copied via ReflectionFactory.copyConstructor.
     */
    private Constructor<T>[] privateGetDeclaredConstructors(boolean publicOnly) {
        Constructor<T>[] res;
        ReflectionData<T> rd = reflectionData();
        if(rd != null) {
            res = publicOnly ? rd.publicConstructors : rd.declaredConstructors;
            if(res != null) {
                return res;
            }
        }
    
        // No cached value available; request value from VM
        if(isInterface()) {
            @SuppressWarnings("unchecked")
            Constructor<T>[] temporaryRes = (Constructor<T>[]) new Constructor<?>[0];
            res = temporaryRes;
        } else {
            res = getDeclaredConstructors0(publicOnly);
        }
    
        if(rd != null) {
            if(publicOnly) {
                rd.publicConstructors = res;
            } else {
                rd.declaredConstructors = res;
            }
        }
    
        return res;
    }
    
    /**
     * Returns an array of "root" methods.
     * These Method objects must NOT be propagated to the outside world, but must instead be copied via ReflectionFactory.copyMethod.
     */
    private Method[] privateGetDeclaredMethods(boolean publicOnly) {
        Method[] res;
        ReflectionData<T> rd = reflectionData();
        if(rd != null) {
            res = publicOnly ? rd.declaredPublicMethods : rd.declaredMethods;
            if(res != null) {
                return res;
            }
        }
    
        // No cached value available; request value from VM
        res = Reflection.filterMethods(this, getDeclaredMethods0(publicOnly));
        if(rd != null) {
            if(publicOnly) {
                rd.declaredPublicMethods = res;
            } else {
                rd.declaredMethods = res;
            }
        }
        return res;
    }
    
    /**
     * Returns an array of "root" methods.
     * These Method objects must NOT be propagated to the outside world, but must instead be copied via ReflectionFactory.copyMethod.
     */
    private Method[] privateGetPublicMethods() {
        Method[] res;
        ReflectionData<T> rd = reflectionData();
        if(rd != null) {
            res = rd.publicMethods;
            if(res != null) {
                return res;
            }
        }
        
        // No cached value available; compute value recursively.
        // Start by fetching public declared methods...
        PublicMethods pms = new PublicMethods();
        for(Method m : privateGetDeclaredMethods(/* publicOnly */ true)) {
            pms.merge(m);
        }
    
        // ...then recur over superclass methods...
        Class<?> sc = getSuperclass();
        if(sc != null) {
            for(Method m : sc.privateGetPublicMethods()) {
                pms.merge(m);
            }
        }
    
        // ...and finally over direct superinterfaces.
        for(Class<?> intf : getInterfaces(/* cloneArray */ false)) {
            for(Method m : intf.privateGetPublicMethods()) {
                // static interface methods are not inherited
                if(!Modifier.isStatic(m.getModifiers())) {
                    pms.merge(m);
                }
            }
        }
        
        res = pms.toArray();
        if(rd != null) {
            rd.publicMethods = res;
        }
    
        return res;
    }
    
    /**
     * Returns a "root" Field object.
     * This Field object must NOT be propagated to the outside world, but must instead be copied via ReflectionFactory.copyField.
     */
    private Field getField0(String name) {
        // Note: the intent is that the search algorithm this routine
        // uses be equivalent to the ordering imposed by
        // privateGetPublicFields(). It fetches only the declared
        // public fields for each class, however, to reduce the number
        // of Field objects which have to be created for the common
        // case where the field being requested is declared in the
        // class which is being queried.
        Field res;
        // Search declared public fields
        if((res = searchFields(privateGetDeclaredFields(true), name)) != null) {
            return res;
        }
        // Direct superinterfaces, recursively
        Class<?>[] interfaces = getInterfaces(/* cloneArray */ false);
        for(Class<?> c : interfaces) {
            if((res = c.getField0(name)) != null) {
                return res;
            }
        }
        // Direct superclass, recursively
        if(!isInterface()) {
            Class<?> c = getSuperclass();
            if(c != null) {
                if((res = c.getField0(name)) != null) {
                    return res;
                }
            }
        }
        return null;
    }
    
    /**
     * Returns a "root" Method object.
     * This Method object must NOT be propagated to the outside world, but must instead be copied via ReflectionFactory.copyMethod.
     */
    private Method getMethod0(String name, Class<?>[] parameterTypes) {
        PublicMethods.MethodList res = getMethodsRecursive(name, parameterTypes == null ? EMPTY_CLASS_ARRAY : parameterTypes,
            /* includeStatic */ true);
        return res == null ? null : res.getMostSpecific();
    }
    
    /**
     * Returns a list of "root" Method objects.
     * These Method objects must NOT be propagated to the outside world, but must instead be copied via ReflectionFactory.copyMethod.
     */
    private PublicMethods.MethodList getMethodsRecursive(String name, Class<?>[] parameterTypes, boolean includeStatic) {
        // 1st check declared public methods
        Method[] methods = privateGetDeclaredMethods(/* publicOnly */ true);
        PublicMethods.MethodList res = PublicMethods.MethodList.filter(methods, name, parameterTypes, includeStatic);
        // if there is at least one match among declared methods, we need not
        // search any further as such match surely overrides matching methods
        // declared in superclass(es) or interface(s).
        if(res != null) {
            return res;
        }
        
        // if there was no match among declared methods,
        // we must consult the superclass (if any) recursively...
        Class<?> sc = getSuperclass();
        if(sc != null) {
            res = sc.getMethodsRecursive(name, parameterTypes, includeStatic);
        }
        
        // ...and coalesce the superclass methods with methods obtained
        // from directly implemented interfaces excluding static methods...
        for(Class<?> intf : getInterfaces(/* cloneArray */ false)) {
            res = PublicMethods.MethodList.merge(res, intf.getMethodsRecursive(name, parameterTypes,
                /* includeStatic */ false));
        }
        
        return res;
    }
    
    /**
     * Returns a "root" Constructor object.
     * This Constructor object must NOT be propagated to the outside world, but must instead be copied via ReflectionFactory.copyConstructor.
     */
    private Constructor<T> getConstructor0(Class<?>[] parameterTypes, int which) throws NoSuchMethodException {
        ReflectionFactory fact = getReflectionFactory();
        Constructor<T>[] constructors = privateGetDeclaredConstructors((which == Member.PUBLIC));
        for(Constructor<T> constructor : constructors) {
            if(arrayContentsEq(parameterTypes, fact.getExecutableSharedParameterTypes(constructor))) {
                return constructor;
            }
        }
        throw new NoSuchMethodException(methodToString("<init>", parameterTypes));
    }
    
    private native Field[] getDeclaredFields0(boolean publicOnly);
    
    private native Method[] getDeclaredMethods0(boolean publicOnly);
    
    private native Constructor<T>[] getDeclaredConstructors0(boolean publicOnly);
    
    private native Class<?>[] getDeclaredClasses0();
    
    /** Helper method to get the method name from arguments. */
    private String methodToString(String name, Class<?>[] argTypes) {
        StringJoiner sj = new StringJoiner(", ", getName() + "." + name + "(", ")");
        if(argTypes != null) {
            for(int i = 0; i<argTypes.length; i++) {
                Class<?> c = argTypes[i];
                sj.add((c == null) ? "null" : c.getName());
            }
        }
        return sj.toString();
    }
    
    private String cannotCastMsg(Object obj) {
        return "Cannot cast " + obj.getClass().getName() + " to " + getName();
    }
    
    private AnnotationData annotationData() {
        while(true) { // retry loop
            AnnotationData annotationData = this.annotationData;
            int classRedefinedCount = this.classRedefinedCount;
            if(annotationData != null && annotationData.redefinedCount == classRedefinedCount) {
                return annotationData;
            }
            // null or stale annotationData -> optimistically create new instance
            AnnotationData newAnnotationData = createAnnotationData(classRedefinedCount);
            // try to install it
            if(Atomic.casAnnotationData(this, annotationData, newAnnotationData)) {
                // successfully installed new AnnotationData
                return newAnnotationData;
            }
        }
    }
    
    private AnnotationData createAnnotationData(int classRedefinedCount) {
        Map<Class<? extends Annotation>, Annotation> declaredAnnotations = AnnotationParser.parseAnnotations(getRawAnnotations(), getConstantPool(), this);
        Class<?> superClass = getSuperclass();
        Map<Class<? extends Annotation>, Annotation> annotations = null;
        if(superClass != null) {
            Map<Class<? extends Annotation>, Annotation> superAnnotations = superClass.annotationData().annotations;
            for(Map.Entry<Class<? extends Annotation>, Annotation> e : superAnnotations.entrySet()) {
                Class<? extends Annotation> annotationClass = e.getKey();
                if(AnnotationType.getInstance(annotationClass).isInherited()) {
                    if(annotations == null) { // lazy construction
                        annotations = new LinkedHashMap<>((Math.max(declaredAnnotations.size(), Math.min(12, declaredAnnotations.size() + superAnnotations.size())) * 4 + 2) / 3);
                    }
                    annotations.put(annotationClass, e.getValue());
                }
            }
        }
    
        if(annotations == null) {
            // no inherited annotations -> share the Map with declaredAnnotations
            annotations = declaredAnnotations;
        } else {
            // at least one inherited annotation -> declared may override inherited
            annotations.putAll(declaredAnnotations);
        }
    
        return new AnnotationData(annotations, declaredAnnotations, classRedefinedCount);
    }
    
    private native Class<?> getNestHost0();
    
    private native Class<?>[] getNestMembers0();
    
    /** annotation data that might get invalidated when JVM TI RedefineClasses() is called */
    private static class AnnotationData {
        final Map<Class<? extends Annotation>, Annotation> annotations;
        final Map<Class<? extends Annotation>, Annotation> declaredAnnotations;
        
        // Value of classRedefinedCount when we created this AnnotationData instance
        final int redefinedCount;
        
        AnnotationData(Map<Class<? extends Annotation>, Annotation> annotations, Map<Class<? extends Annotation>, Annotation> declaredAnnotations, int redefinedCount) {
            this.annotations = annotations;
            this.declaredAnnotations = declaredAnnotations;
            this.redefinedCount = redefinedCount;
        }
    }
    
    /** Atomic operations support. */
    private static class Atomic {
        // initialize Unsafe machinery here, since we need to call Class.class instance method
        // and have to avoid calling it in the static initializer of the Class class...
        private static final Unsafe unsafe = Unsafe.getUnsafe();
        // offset of Class.reflectionData instance field
        private static final long reflectionDataOffset = unsafe.objectFieldOffset(Class.class, "reflectionData");
        // offset of Class.annotationType instance field
        private static final long annotationTypeOffset = unsafe.objectFieldOffset(Class.class, "annotationType");
        // offset of Class.annotationData instance field
        private static final long annotationDataOffset = unsafe.objectFieldOffset(Class.class, "annotationData");
        
        static <T> boolean casReflectionData(Class<?> clazz, SoftReference<ReflectionData<T>> oldData, SoftReference<ReflectionData<T>> newData) {
            return unsafe.compareAndSetObject(clazz, reflectionDataOffset, oldData, newData);
        }
        
        static <T> boolean casAnnotationType(Class<?> clazz, AnnotationType oldType, AnnotationType newType) {
            return unsafe.compareAndSetObject(clazz, annotationTypeOffset, oldType, newType);
        }
        
        static <T> boolean casAnnotationData(Class<?> clazz, AnnotationData oldData, AnnotationData newData) {
            return unsafe.compareAndSetObject(clazz, annotationDataOffset, oldData, newData);
        }
    }
    
    /**
     * Reflection data caches various derived names and reflective members.
     * Cached values may be invalidated when JVM TI RedefineClasses() is called
     */
    private static class ReflectionData<T> {
        static final String NULL_SENTINEL = new String();
        // Value of classRedefinedCount when we created this ReflectionData instance
        final int redefinedCount;
        volatile Field[] declaredFields;
        volatile Field[] publicFields;
        volatile Method[] declaredMethods;
        volatile Method[] publicMethods;
        volatile Constructor<T>[] declaredConstructors;
        volatile Constructor<T>[] publicConstructors;
        // Intermediate results for getFields and getMethods
        volatile Field[] declaredPublicFields;
        volatile Method[] declaredPublicMethods;
        volatile Class<?>[] interfaces;
        // Cached names
        String simpleName;
        String canonicalName;
        
        ReflectionData(int redefinedCount) {
            this.redefinedCount = redefinedCount;
        }
    }
    
    private static final class EnclosingMethodInfo {
        private final Class<?> enclosingClass;
        private final String name;
        private final String descriptor;
        
        EnclosingMethodInfo(Object[] enclosingInfo) {
            validate(enclosingInfo);
            this.enclosingClass = (Class<?>) enclosingInfo[0];
            this.name = (String) enclosingInfo[1];
            this.descriptor = (String) enclosingInfo[2];
        }
        
        static void validate(Object[] enclosingInfo) {
            if(enclosingInfo.length != 3)
                throw new InternalError("Malformed enclosing method information");
            try {
                // The array is expected to have three elements:
                
                // the immediately enclosing class
                Class<?> enclosingClass = (Class<?>) enclosingInfo[0];
                assert (enclosingClass != null);
                
                // the immediately enclosing method or constructor's
                // name (can be null).
                String name = (String) enclosingInfo[1];
                
                // the immediately enclosing method or constructor's
                // descriptor (null iff name is).
                String descriptor = (String) enclosingInfo[2];
                assert ((name != null && descriptor != null) || name == descriptor);
            } catch(ClassCastException cce) {
                throw new InternalError("Invalid type in enclosing method information", cce);
            }
        }
        
        boolean isPartial() {
            return enclosingClass == null || name == null || descriptor == null;
        }
        
        boolean isConstructor() {
            return !isPartial() && "<init>".equals(name);
        }
        
        boolean isMethod() {
            return !isPartial() && !isConstructor() && !"<clinit>".equals(name);
        }
        
        Class<?> getEnclosingClass() {
            return enclosingClass;
        }
        
        String getName() {
            return name;
        }
        
        String getDescriptor() {
            return descriptor;
        }
    }
}