Creating Applets
1. What Is an Applet? (beginner)
Applet = small Java program living in web page (browser ran it!). No main — browser calls init/start/paint/stop/destroy lifecycle! Historical (browsers dropped support ~2018 for security!) but exams still ask!
2. Lifecycle (exam order — memorize!)
import java.applet.Applet; // deprecated now! (exam still!)
import java.awt.*;
public class Hi extends Applet { // extends Applet (not Frame!)
public void init() { setBackground(Color.YELLOW); } // 1. born (once!)
public void start() { System.out.println("visible!"); } // 2. shown (many!)
public void paint(Graphics g) { g.drawString("hi web!", 20, 20); } // 3. draw!
public void stop() { System.out.println("hidden!"); } // 4. minimized!
public void destroy() { System.out.println("dead!"); } // 5. closed!
}
HTML to run (old!): <applet code="Hi.class" width="300" height="200"></applet>
3. Applet vs Application (exam table!)
| Applet | Application (Frame!) | |
|---|---|---|
| Entry | init() (browser!) |
main() (JVM!) |
| Window | browser page (no title!) | own Frame! |
| Security | sandboxed (no files!) | full access! |
| Run | HTML + browser/plugin | java Class! |
4. Modern Note (viva smart line!)
Browsers REMOVED applet plugins (security!). Today: same code as JPanel + JFrame, or Java Web Start / plain web apps. Learn lifecycle for exams, build Swing/Frame for real!
5. Exam Points
- Lifecycle + program — 7 marks, very frequent.
- Applet vs application — 5 marks, frequent.