Some customers of dbx use the low level bytecode stepping functionality
available to step through the bytecodes and debug their code. As
a part of this exercise they would like to see a dump of the
current java operand stack.
The hotspot VM does not implement or document these functions which
are present in the jvmdi.h file.
    jvmdiError (JNICALL *GetOperandStack)
      (jframeID frame, jint *operandStackSizePtr,
       JVMDI_operand_stack_element **operandStackPtr);
    jvmdiError (JNICALL *SetOperandStack)
      (jframeID frame, jint operandStackSize,
       JVMDI_operand_stack_element *operandStack);
Implementing these in the VM will help dbx implement a command to dump
the current java stack for users who do bytecode level debugging.