あｐｐぇｐｐｌ

import java.applet.Applet;
import java.awt.Graphics;
import java.awt.Color;
import java.awt.Dimension;

public class pro extends Applet{
  public void paint(Graphics g){
    g.setColor(Color.red);

    Dimension size = getSize();
    g.fillRect(0, 0, size.width - 1, size.height - 1);
  }
}