There are two different Frames in my program and the second one open when i click the jButton is the first frame,so when the second frame is opened, I want the second frame
JFrame frame = new JFrame ();
frame.setAlwaysOnTop (true);
If you want frame to be always focused, you probably need to use modal dialog instead of JFrame:
JDialog dialog = new JDialog ();
dialog.setModal (true);
dialog.setAlwaysOnTop (true);
dialog.setModalityType (ModalityType.APPLICATION_MODAL);