how to create new graphics class in java code example

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

public void paintComponent(Graphics g) {
   super.paintComponent(g);
   int width =  getWidth();   // Find out the width of this component.
   int height = getHeight();  // Find out its height.
   . . .   // Draw the content of the component.
}

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

public void repaint();

Example 3: Write a simple java swing application that will display rectangle graphics as shown in the picture below:

public void paintComponent(g) {
   super.paintComponent(g);
   . . . // Draw the content of the component.
}