Swing from Jython - threading issues

threads.py

import threading

from javax.swing import JFrame, JButton
from java.awt.event import ActionListener, WindowAdapter

class Frame(JFrame, ActionListener):
    def __init__(self):
        print "constructing! thread is %s" % threading.currentThread()
        button = JButton("Hello")
        button.setActionCommand('button')
        button.addActionListener(self)
        self.getContentPane().add(button)
        self.pack()
        self.setResizable(False)

    # @Override
    def actionPerformed(self, event):
        print "event! thread is %s" % threading.currentThread()


endCondition = threading.Condition()
class Adapter(WindowAdapter):
    # @Override
    def windowClosing(self, event):
        endCondition.acquire()
        endCondition.notifyAll()
        endCondition.release()


if __name__ == '__main__':
    endCondition.acquire()

    frame = Frame()
    frame.setVisible(True)
    frame.addWindowListener(Adapter())

    # We don't use setDefaultCloseOperation(EXIT_ON_CLOSE), which would call
    # Java's System.exit() instead of Python's sys.exit()
    endCondition.wait()
    endCondition.release()

    print 'sys.exit()'
    sys.exit(0)