Dumpclass

Dump classes from running JVM process by sa-jdi.jar.

• Support wildcard match

• Support multi classloader

Download dumpclass.jar

You can download dumpclass.jar from maven center.

http://search.maven.org/#search%7Cga%7C1%7Cdumpclass

Usage

Usage:
 java -jar dumpclass.jar <pid> <pattern> [outputDir] <--classLoaderPrefix>

pattern: support ? * wildcard match.
outputDir: default outputDir is current directory.
--classLoaderPrefix: every classloader has it's own output directory. When multi classloaders load same name classes, try this.

Example:
 java -jar dumpclass.jar 4345 *StringUtils
 java -jar dumpclass.jar 4345 *StringUtils /tmp
 java -jar dumpclass.jar 4345 *StringUtils /tmp --classLoaderPrefix

Use the specified sa-jdi.jar:
 java -cp "./dumpclass.jar:$JAVA_HOME/lib/sa-jdi.jar" io.github.hengyunabc.dumpclass.DumpMain <pid> <pattern> [outputDir]

Trouble

• Try to use sudo

Error attaching to process: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process. Could be caused by an incorrect pid or lack of privileges.
sun.jvm.hotspot.debugger.DebuggerException: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process. Could be caused by an incorrect pid or lack of privileges.
	at sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal$BsdDebuggerLocalWorkerThread.execute(BsdDebuggerLocal.java:169)
	at sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal.attach(BsdDebuggerLocal.java:287)
	at sun.jvm.hotspot.HotSpotAgent.attachDebugger(HotSpotAgent.java:671)
	at sun.jvm.hotspot.HotSpotAgent.setupDebuggerDarwin(HotSpotAgent.java:659)
	at sun.jvm.hotspot.HotSpotAgent.setupDebugger(HotSpotAgent.java:341)
	at sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:304)
	at sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:140)
	at sun.jvm.hotspot.tools.Tool.start(Tool.java:185)
	at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118)
	at sun.jvm.hotspot.tools.jcore.ClassDump.main(ClassDump.java:180)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at io.github.hengyunabc.dumpclass.DumpMain.main(DumpMain.java:101)
Caused by: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process. Could be caused by an incorrect pid or lack of privileges.
	at sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal.attach0(Native Method)
	at sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal.access$100(BsdDebuggerLocal.java:65)
	at sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal$1AttachTask.doit(BsdDebuggerLocal.java:278)
	at sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal$BsdDebuggerLocalWorkerThread.run(BsdDebuggerLocal.java:144)

• Make sure use the same jdk version.

Attaching to process ID 53577, please wait...
Exception in thread "main" java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at io.github.hengyunabc.dumpclass.DumpMain.main(DumpMain.java:101)
Caused by: java.lang.InternalError: void* type hasn't been seen when parsing int*
	at sun.jvm.hotspot.HotSpotTypeDataBase.recursiveCreateBasicPointerType(HotSpotTypeDataBase.java:721)
	at sun.jvm.hotspot.HotSpotTypeDataBase.lookupType(HotSpotTypeDataBase.java:134)
	at sun.jvm.hotspot.HotSpotTypeDataBase.lookupOrCreateClass(HotSpotTypeDataBase.java:631)
	at sun.jvm.hotspot.HotSpotTypeDataBase.createType(HotSpotTypeDataBase.java:751)
	at sun.jvm.hotspot.HotSpotTypeDataBase.readVMTypes(HotSpotTypeDataBase.java:195)
	at sun.jvm.hotspot.HotSpotTypeDataBase.<init>(HotSpotTypeDataBase.java:89)
	at sun.jvm.hotspot.HotSpotAgent.setupVM(HotSpotAgent.java:403)
	at sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:305)
	at sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:140)
	at sun.jvm.hotspot.tools.Tool.start(Tool.java:185)
	at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118)
	at sun.jvm.hotspot.tools.jcore.ClassDump.main(ClassDump.java:180)
	... 5 more

• One class loaded by multi ClassLoader

Try to use HSDB. After attach java process, "Tools", "Class Browser".

sudo java -classpath "$JAVA_HOME/lib/sa-jdi.jar" sun.jvm.hotspot.HSDB

complie dumpclass.jar

mvn clean package
ls -alh target

##License

Apache License V2