Debugging with GDB Manual The GNU Source-Level Debugger (769148-001, March 2014)

export GDB_JAVA_UNWINDLIB = /opt/java1.4/jre/lib/PA_RISC/server/libjunwind.sl
• For 64-bit PA applications,
export GDB_JAVA_UNWINDLIB = /opt/java1.4/jre/lib/PA_RISC2.0/server/libjunwind.sl
export GDB_JAVA_UNWINDLIB = /opt/java1.4/jre/lib/PA_RISC2.0W/server/libjunwind.sl
If the SDK is installed in a location other than the default, substitute the non-default location for
/opt/java1.4 in the previous commands.
Java Stack Unwind Features
The Java stack unwind features are useful for troubleshooting problems in the Java VM. Following
is a list of the Java stack unwind features:
• View mixed language frames information, including Java frames and C/C++ native frames,
in a gdb backtrace.
• Distinguish various Java frame types including interpreted, compiled, and adapter frames.
• View Java method name, signature, and class package name for Java method frames.
Additional stack unwind features are available starting with SDK 1.4.2. These features fall into
three categories: Java stack unwind enhancements, Java heap support, and Java threads support.
These additional features are available as part of the Java stack unwind enhancements:
• View Java compiled frame inlined methods.
• View Java interpreted or compiled frame specific information.
• View Java interpreted or compiled frame arguments and local variables.
• Disassemble Java method bytecodes.
• Print out the Java unwind table.
These additional features are available as part of Java heap support:
• View Java heap parameters.
• Dump Java object.
• Print Java heap histogram.
• Find all the instances of a given Java class.
• Find all the references to a given object in the Java heap.
• Find out the object OOP (object-oriented pointer) of the given field address.
These additional features are available as part of Java threads support:
• View Java threads state information.
• View current Java thread information.
• View Java interpreted frame monitors information.
gdb Subcommands for Java VM Debugging
Commands for Examining Java Virtual Machine(JVM) internals
To view the gdb commands that support Java VM debugging, type help java at the gdb prompt.
(gdb) help java
Java and JVM debugging commands.
List of java subcommands:
java args -- Show the current or specified Java frame arguments info
java bytecodes -- Disassemble the given Java method's bytecodes
java heap-histogram -- Show the Java heap object histogram
java instances -- Find all the instances of the given klassOop in the Java heap
Language support 165