Error.java

/*
 * Copyright (c) 1995, 2011, 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;

/**
 * An {@code Error} is a subclass of {@code Throwable}
 * that indicates serious problems that a reasonable application
 * should not try to catch. Most such errors are abnormal conditions.
 * The {@code ThreadDeath} error, though a "normal" condition,
 * is also a subclass of {@code Error} because most applications
 * should not try to catch it.
 * <p>
 * A method is not required to declare in its {@code throws}
 * clause any subclasses of {@code Error} that might be thrown
 * during the execution of the method but not caught, since these
 * errors are abnormal conditions that should never occur.
 *
 * That is, {@code Error} and its subclasses are regarded as unchecked
 * exceptions for the purposes of compile-time checking of exceptions.
 *
 * @author Frank Yellin
 * @jls 11.2 Compile-Time Checking of Exceptions
 * @see java.lang.ThreadDeath
 * @since 1.0
 */
/*
 * 错误，一般指虚拟机内部的异常
 *
 * 异常体系：
 *                           Throwable
 *                               |
 *                    +----------+-----------+
 *                    |                      |
 *                Exception                Error
 *                    |                      |
 *        +-----------+-----------+         ...
 *        |                       |
 * RuntimeException              ...
 *        |
 *       ...
 *
 * Throwable       : 所有异常的祖先类
 * RuntimeException: 运行时异常，或称非检查异常；这类异常意味着程序出现了难以恢复的错误，允许不进行捕获
 * Exception       : 除运行时异常之外的异常，或称检查异常；这类异常意味着程序出现错误时可能是允许被恢复的，需要在编译期就捕获，否则无法编译
 * Error           : 非常严重的异常，该类异常往往意味着JVM内部出现了问题
 */
public class Error extends Throwable {
    
    static final long serialVersionUID = 4980196508277280342L;
    
    /**
     * Constructs a new error with {@code null} as its detail message.
     * The cause is not initialized, and may subsequently be initialized by a
     * call to {@link #initCause}.
     */
    public Error() {
        super();
    }
    
    /**
     * Constructs a new error with the specified detail message.  The
     * cause is not initialized, and may subsequently be initialized by
     * a call to {@link #initCause}.
     *
     * @param message the detail message. The detail message is saved for
     *                later retrieval by the {@link #getMessage()} method.
     */
    public Error(String message) {
        super(message);
    }
    
    /**
     * Constructs a new error with the specified detail message and
     * cause.  <p>Note that the detail message associated with
     * {@code cause} is <i>not</i> automatically incorporated in
     * this error's detail message.
     *
     * @param message the detail message (which is saved for later retrieval
     *                by the {@link #getMessage()} method).
     * @param cause   the cause (which is saved for later retrieval by the
     *                {@link #getCause()} method).  (A {@code null} value is
     *                permitted, and indicates that the cause is nonexistent or
     *                unknown.)
     *
     * @since 1.4
     */
    public Error(String message, Throwable cause) {
        super(message, cause);
    }
    
    /**
     * Constructs a new error with the specified cause and a detail
     * message of {@code (cause==null ? null : cause.toString())} (which
     * typically contains the class and detail message of {@code cause}).
     * This constructor is useful for errors that are little more than
     * wrappers for other throwables.
     *
     * @param cause the cause (which is saved for later retrieval by the
     *              {@link #getCause()} method).  (A {@code null} value is
     *              permitted, and indicates that the cause is nonexistent or
     *              unknown.)
     *
     * @since 1.4
     */
    public Error(Throwable cause) {
        super(cause);
    }
    
    /**
     * Constructs a new error with the specified detail message,
     * cause, suppression enabled or disabled, and writable stack
     * trace enabled or disabled.
     *
     * @param message            the detail message.
     * @param cause              the cause.  (A {@code null} value is permitted,
     *                           and indicates that the cause is nonexistent or unknown.)
     * @param enableSuppression  whether or not suppression is enabled
     *                           or disabled
     * @param writableStackTrace whether or not the stack trace should
     *                           be writable
     *
     * @since 1.7
     */
    protected Error(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
    }
}