What is the reason for KeyListener not responding to keypresses? Java Swing?

Question

Java

Strange bug, temporary. That is, he is, then he is not. Then everything works OK, then after a couple of restarts, the window stops responding to keystrokes.

At the same time, the isFocusable == trueelements JMenuBarare available, they work. But the window does not react to any key presses.

isFocusedand isActivealsotrue

Answer 1

you can hang the processing of individual combinations on the window and all its descendants:
getRootPane().registerKeyboardAction(actionListener, "cancel", KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE, 0),
JComponent.WHEN_IN_FOCUSED_WINDOW);
True, the Documentation says that the method is deprecated and instead you need to use a combination:
component.getInputMap().put(aKeyStroke, aCommand);
component.getActionMap().put(aCommand, anAction);

Answer 2

Indeed, what exactly did you hang the KeyListener on and where exactly do you press the buttons?