Thread: ActionListener in Java

I wonder whether everything else stops while ActionListener running?
If I loop a button ActionListener when this button is pressed, I can not invoke another button ActionListener
I want to toggle 2 actions of 2 buttons:
- Press btn1 --> do btn1 ActionListener
{ Flag1 = true, Flag2 = false
while Flag1 = true, do action1
}

- Press btn2 --> do btn2 ActionListener
{ Flag1 = false, Flag2 = true
while Flag2 = true, do action2
}

But when invoke btn1, everything else is out of control

Originally Posted by Norm

ActionListeners run on the Event Dispatch Thread which is the same thread used by Swing. If any code running on the EDT uses too much time, the responsiveness of all GUI components will be delayed until the code using the EDT ends.

If there is a need for a long running task, better to have the code for that task run on its own, separate thread.

In this case, if a button invokes to sound a midi note, how can you prolong the sound until you click the button STOP or another button?