java how to paint on command graphics code example

Example 1: Write a simple java swing application that will display rectangle graphics as shown in the picture below:

import javax.swing.JApplet;

/**
 * A RandomStringsApplet displays 25 copies of a string, using random colors,
 * fonts, and positions for the copies.  The message can be specified as the
 * value of an applet param with name "message."  If no param with name
 * "message" is present, then the default message "Java!" is displayed.
 * The actual content of the applet is an object of type RandomStringsPanel.
 */
public class RandomStringsApplet extends JApplet {
   
   public void init() {
      String message = getParameter("message");
      RandomStringsPanel content = new RandomStringsPanel(message);
      setContentPane(content);
   }

}

Example 2: Write a simple java swing application that will display rectangle graphics as shown in the picture below:

// Graphics context's current color.
void setColor(Color c)
Color getColor()
 
// Graphics context's current font.
void setFont(Font f)
Font getFont()

// Set/Get the current clip area. Clip area shall be rectangular and no rendering is performed outside the clip area.
void setClip(int xTopLeft, int yTopLeft, int width, int height)
void setClip(Shape rect)
public abstract void clipRect(int x, int y, int width, int height) // intersects the current clip with the given rectangle
Rectangle getClipBounds()  // returns an Rectangle
Shape getClip()            // returns an object (typically Rectangle) implements Shape