Debugging with GDB (September 2007)

174 Debugging with GDB

14.21.2 Commands for Examining Java Virtual Machine(JVM)

internals

The following commands can be used to obtain information on Java VM internals:

help java

Prints list of Java and JVM debugging commands

java Prints list of java subc ommands

14.21.2.1 Java subcommands

The following Java sub com mands have been added:

java args <frame-number>

Prints the current or speciﬁed Java frame arguments information

java bytecodes <methodOop>

Disassembles the given Java method bytecode

java heap-histogram

Displays the Java heap object histogram

java instances <klassOop>

Locates the instances of the given klassOop in the Java heap.

java jvm-state

Prints current status of JVM internal states

java locals

Prints the current or speciﬁed Java frame locals information

java mutex-info

Prints details of static mutexes

java object <object-ptr>

Prints the given Java object ﬁeld information

java oop <Java_heap_address>

Locates Java object oop of the given Java heap address

java references <oop>

Locates references to the given Java object in the Java heap

java unwind-info <pc>

Prints unwind information of the code where the PC is located

java unwind-table

Prints the dynamically generated Java Unwind Table

14.21.3 Support for stack traces in Java, C, and C++ programs

HP WDB shows stack traces of mixed Java, C, and C++ programs. The stack trace

functionality requires Java SDK version 1.3.1.02 or later for HP-UX. To ﬁnd the