How to capture a JFrame's close button click event?

Question

I want to call a method confirmExit() when the red close button of the title bar of a JFrame is clicked.

How can I capture that event?

I'd also like to prevent the window from closing if the user chooses not to proceed.

Answer 1

import javax.swing.JOptionPane; import javax.swing.JFrame;  /*Some piece of code*/ frame.addWindowListener(new java.awt.event.WindowAdapter() {     @Override     public void windowClosing(java.awt.event.WindowEvent windowEvent) {         if (JOptionPane.showConfirmDialog(frame,              "Are you sure you want to close this window?", "Close Window?",              JOptionPane.YES_NO_OPTION,             JOptionPane.QUESTION_MESSAGE) == JOptionPane.YES_OPTION){             System.exit(0);         }     } }); 

If you also want to prevent the window from closing unless the user chooses 'Yes', you can add:

frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);