active window without showing it or bringing it to top

Question

I want a function that I can't find wish allow to activate a window, without showing it.

Answer 1

Finally found the answer:

a minimized window can't be active, and there is a way to communcate with hidden windows (if not minimized using messages)

Answer 2

If this window is a subclass of java.awt.Window you can call setVisible to hide it.