Java JButton handle click event via lambda expression
import java.awt.FlowLayout; import javax.swing.JButton; import javax.swing.JFrame; public class Main extends JFrame { public Main() { super("demo from demo2s.com"); JButton closeButton = new JButton("Close"); setDefaultCloseOperation(EXIT_ON_CLOSE); setLayout(new FlowLayout()); getContentPane().add(closeButton);/*from w w w . j a v a2 s . c om*/ closeButton.addActionListener(e -> System.exit(0)); } public static void main(String[] args) { Main frame = new Main(); frame.pack(); frame.setVisible(true); } }