get current StackFrame thru JDI

[Ken.C]

Hi,
I did Google search but didn't get much useful info...
Basically, I encountered IndexOutOfBoundsException when trying to get
current stack frame:
1 void methodEntryEvent(MethodEntryEvent event) {
2 Method method = event.method();
3 ThreadReference thread = (ThreadReference) event.thread();
4 try {
5 StackFrame stackFrame = thread.frame(0);
.............
}
catch(IncompatibleThreadStateException e){
........
}
}

The exception occurred at line 5. Test codes running on the target VM
are:

public static void main(String[] args) {
String name = "Someone";
System.out.println(foo(name));
}

private static String foo(String name) {
System.out.println(bar(888));
return "Hi, " + name + ".";
}

private static int bar(int a) {
return 999;
}

Does anyone know why the stack counter is always 0 in my codes?

Thanks a lot

 

[Chris Uppal]

Does anyone know why the stack counter is always 0 in my codes?

I know very little about JDI, but no one else has replied so....

Was the thread suspended at the time the event was generated ? If not then I
doubt whether frames are available (since the thread will have gone on
executing while the event was passed through the event queue). See the
documentation for

EntryRequest.setSuspendPolicy(EventRequest.SUSPEND_ALL)

And then you'll have to resume() the target ThreadReference. There's more
documentation about it, but I've only skimmed that -- you should probably read
it more carefully than me ;-)

-- chris