Programatically controlling objects in another VM

Question

I need to programatically get and modify objects in another VM.
How can I do this? I already use JDI, but until now I only get references, not the real things.
And I am not sure, if JDI allows me to modify objects in another VM, invoke methods etc.
But it must work somehow, because all this is possible when debugging in an IDE like in Eclipse. But its too hard to understand all their large implementation.
Are there any small code pieces which simply show me exactly how I can access objects in another VM (no references) and modify them inside the other VM from another VM?
Until now I have something like this:
Class clazz = Class.forName("com.sun.tools.jdi.SocketTransportService");
TransportService ts = (TransportService) clazz.newInstance();
Connection connection = ts.attach("localhost:8000", 0, 0);
VirtualMachineManager vmm = Bootstrap.virtualMachineManager();
VirtualMachine vm = vmm.createVirtualMachine(connection);
List allThreads = vm.allThreads();
The elements in the collection are actuall of type ThreadReferenceImpl. I already discovered that I need to suspend the thread and walk the stack trace in order to get the object I want and then to resume the thread (but I found only references). Thats the basic idea. I wonder if that works, and if yes, how. Please no guesses.

Answer 1

Check out the jdb source code in <jdk>/demo/jpda/examples.jar. You can find calls to ObjectReference.setValue(value) and invokeMethod(...).