Hi Hiep,
Double clicks are difficult to catch in Swing. You need to check for a double click in the "mouseReleased()" method (of the "MouseListener" interface). In (your implementation of) that method, you need to invoke the "getClickCount()" method (of class "MouseEvent"). Note that each click of the mouse button will fire a "mouse event", so your "mouseReleased()" method will get called twice. The first time, "getClickCount()" will return 1 (one), and the second time it will return 2 (two). However, "getClickCount()" will only return two if the mouse button was clicked twice quickly. In other words, you may click the mouse button twice, but it won't be fast enough for
java to realize that it's a double click. (I told you that catching double clicks in swing is difficult :-)
Hope this helps you.
Good Luck,
Avi.