Every applet must subclass Applet.

    import java.applet.*;
    import java.awt.*;
    
    public class BasicApplet extends Applet {
        // This method is called once by the browser when it starts the applet.
        public void init() {
        }
    
        // This method is called whenever the page containing this applet is made visible.
        public void start() {
        }
    
        // This method is called whenever the page containing this applet is not visible.
        public void stop() {
        }
    
        // This method is called once when the browser destroys this applet.
        public void destroy() {
        }
    
        // This method is called whenever this applet needs to repaint itself.
        public void paint(Graphics g) {
        }
    }

Here is an example of an HTML file that will cause the browser to load and start the applet:

    <applet code=BasicApplet width=100 height=100>
    </applet>

e551. 精简的Applet