AWT event-handling example

import java.awt.*;
import java.awt.event.*;

public class GreetingApp {
    public static void main(String[] args) {
        Frame frame = new Frame("Greeting");
        Label label = new Label("Enter your name:");
        TextField input = new TextField(18);
        Button button = new Button("Greet");
        Label output = new Label(" ");
        Panel panel = new Panel();
        panel.add(label); panel.add(input); panel.add(button); panel.add(output);
        button.addActionListener(e -> output.setText("Hello, " + input.getText()));
        frame.add(panel);
        frame.setSize(420, 120);
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) { frame.dispose(); }
        });
        frame.setVisible(true);
    }
}

The button is the event source. addActionListener registers a listener; a click generates an ActionEvent and invokes the handler. The window listener closes the frame cleanly.