An alternate approach

import java.awt.*;


public class ColoredOval extends Canvas {

  public ColoredOval() {
    this(Color.RED, 100, 100);
  }

  public ColoredOval(Color c) {
    this(c, 100, 100);
  }

  public ColoredOval(int width, int height) {
    this(Color.RED, width, height);
  }

  public ColoredOval(Color c, int width, int height) {
    this.setColor(c);
    this.setSize(width, height);
  }

  public void paint(Graphics g) {  
    Dimension d = this.getSize();
    g.fillOval(0, 0, d.width, d.height);
  }

}

This is almost but not quite the same effect as the previous applet. (It's a little less resizeable.)