InvalidStackFrameException After Calling Method via ObjectReference#invokeMethod

Question

I am currently working on an Eclipse plugin which enhances the debugging possibilities. During the debugging session, I invoke a Scala method via com.sun.jdi.ObjectReference#invokeMethod like that:

public int callMethod_Reactive_Level(final ObjectReference o) throws InvalidTypeException, ClassNotLoadedException, IncompatibleThreadStateException, InvocationException {
    final Method m = apiValues.getMethod_Reactive_level(o); // com.sun.jdi.Method
    final IntegerValue intVal = (IntegerValue) o.invokeMethod(thread, m, new LinkedList<Value>(), ObjectReference.INVOKE_SINGLE_THREADED);
    return intVal.intValue();
}

After doing that, a call to org.eclipse.debug.core.model.IVariable#getValue leads to an InvalidStackFrameException. The whole error message is:

Status ERROR: org.scala-ide.sdt.debug code=5010 Exception while retrieving variable's value com.sun.jdi.InvalidStackFrameException

The message Exception while retrieving variable's value is shown when I inspect a variable in the variables view after calling a method as shown above.

Any idea how this problem can be solved? I do not understand why this is so problematic, since the JDI explicitely provides the possibility to do that.

Update: Since it may be a bug in the Scala IDE, there is a discussion and a tutorial how to reproduce the issue in the Scala IDE dev group.

Answer 1

The error message seems to come from the Scala IDE implementation of IVariable.getValue. It delegates to the JDI StackFrame.getValue, which throws. According to the docs, this can happen "if this stack frame has become invalid. Once the frame's thread is resumed, the stack frame is no longer valid."

My guess is that executing an invokeMethod on the same thread invalidates the stack frame.