Applet with Swing Components

Applet with Swing Components

1. What Is Swing? (beginner upgrade!)

Swing (javax.swing) = pretty AWT replacement: JButton (vs Button!), JFrame (vs Frame!), JApplet (vs Applet!). Lightweight (Java-drawn, same everywhere!), pluggable look, more widgets (tables, trees!).

2. AWT vs Swing (exam table!)

	AWT	Swing
Package	java.awt	javax.swing (J-prefix!)
Weight	heavyweight (OS peers!)	lightweight (Java!)
Look	native (differs!)	same + LaF (Metal/Nimbus!)
Widgets	few	many (JTable, JTree!)
Close	manual listener!	setDefaultCloseOperation(EXIT_ON_CLOSE)!

3. Code — Same App, Both Ways!

// AWT applet (old!)
import java.applet.Applet;
import java.awt.Button;
public class A extends Applet { public void init() { add(new Button("ok")); } }
// Swing applet (nicer!)
import javax.swing.*;
public class S extends JApplet { // JApplet!
    public void init() { add(new JButton("ok")); } // J-prefix!
}
// Modern desktop (no browser!):
JFrame f = new JFrame("Hi");
f.add(new JButton("ok"));
f.setSize(250, 150);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // auto-close! (no listener!)
f.setVisible(true);

4. Traps

• Swing needs EDT for big apps (SwingUtilities.invokeLater — viva point!).
• JApplet deprecated too (like Applet!). Learn pattern, build JFrame/JPanel real!
• Mix AWT + Swing heavy/light = paint bugs (avoid mixing!).

5. Exam Points

• AWT vs Swing table + program — 7 marks, very frequent.
• J-prefix + close-operation — 3 marks, frequent.