import java.beans.*; static AutoCloseable awt_onGlobalFocusChange(final VF1 f) { final KeyboardFocusManager fm = KeyboardFocusManager.getCurrentKeyboardFocusManager(); final PropertyChangeListener listener = new { public void propertyChange(PropertyChangeEvent e) { if (eq(e.getPropertyName(), "focusOwner")) pcallF(f, e); } }; fm.addPropertyChangeListener(listener); ret autoCloseable { fm.removePropertyChangeListener(listener); }; }