How to Close a Window in Java

Using javax.swing.JFrame

1. 
   Obtain an instance of a JFrame, or create a new one.
2. 
   Set default close operation. Default close operation is set using the setter method inside the JFrame class setDefaultCloseOperation that determines what happens when the close button is clicked and takes the following parameters:

   1. WindowConstants.EXIT_ON_CLOSE - Closes the frame and terminates the execution of the program.
   2. WindowConstants.DISPOSE_ON_CLOSE - Closes the frame and does not necessarily terminate the execution of the program.
   3. WindowConstants.HIDE_ON_CLOSE - Makes the frame appear like it closed by setting its visibility property to false. The difference between HIDE_ON_CLOSE and DISPOSE_ON_CLOSE is that the latter releases all of the resources used by the frame and its components.
   4. WindowConstants.DO_NOTHING_ON_CLOSE - Does nothing when the close button is pressed. Useful if you wish to, for example, display a confirmation dialog before the window is closed. You can do that by adding a WindowListener to the frame and overriding windowClosing method. Example of the custom close operation:

      frame.setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE); frame.addWindowListener(new WindowAdapter() { @Override public void windowClosing(WindowEvent e) { // Ask for confirmation before terminating the program. int option = JOptionPane.showConfirmDialog( frame, "Are you sure you want to close the application?", "Close Confirmation", JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE); if (option == JOptionPane.YES_OPTION) { System.exit(0); } } });