java - JACOB doesn't release the objects properly

Question

I have an eclipse plugin, which connects to a COM component using Jacob. But after I close the plugin entirely, the .exe file stays hanging in Windows processes.

I use ComThread.InitMTA(true) for initialization and make sure that SafeRelease() is called for every COM object I created before closing the app and I call ComThread.Release() at the very end.

Do I leave something undone?

Answer 1

Some further suggestions:

1. Move the call to ComThread.Release() into a finally block, otherwise the thread will remain attached if an exception is thrown.

2. Check that you are calling ComThread.InitMTA and ComThread.Release in every thread that uses a COM object. If you forget to do this in a worker thread then that thread will be attached automatically and never detached.

3. Avoid InitSTA and stick to InitMTA. Even when there is only one thread using COM, I have found InitSTA to be flaky. I don't know how JACOB's internal marshalling mechanism works but I have ended up with "ghost" objects that appear to be valid but do nothing when their methods are invoked.

Fortunately I have never yet needed to modify any code in the JACOB library.