WindowAdapter.windowLostFocus(WindowEvent e) has the following syntax.
public void windowLostFocus(WindowEvent e)
In the following code shows how to use WindowAdapter.windowLostFocus(WindowEvent e) method.
import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.swing.JFrame; public class Main { JFrame window = new JFrame("Main"); public Main() { window.setBounds(30, 30, 300, 300);// w w w . ja v a 2 s.c om window.addWindowListener(new WindowHandler()); window.setVisible(true); } class WindowHandler extends WindowAdapter { public void windowLostFocus(WindowEvent e) { System.out.println("windowLostFocus"); window.dispose(); // Release the window resources System.exit(0); // End the application } } public static void main(String[] args) { new Main(); } }