Adjusting the Star Size

The size of the star should be based on the current width and height of the frame. These might not be the same value. The size should be based on whichever is smaller so the star will fit. paintComponent does this with an if statement:

  public void paintComponent ( Graphics gr )
  { 
    int width  = getWidth();
    int height = getHeight();
    int min;
    
    super.paintComponent( gr );
    setBackground(Color.white);
    gr.setColor( Color.blue );
          
    if ( height > width )
      min = height;
    else
      min = width;
   
    drawStar( gr, width/2, height/2, min/4 );
  }

The drawStar( Graphics gr, int x, int y, int size ) method draws a six-pointed star centered at (x, y). Each line of the star is size pixels long.