Cuadrado de 100x100 pixeles

Codigo para mostrar un cuadrado de 100x100 pixeles empezando en la coordenada 10,10

import java.awt.Color;

import java.awt.Container;

import java.awt.Dimension;

import java.awt.FlowLayout;

import java.awt.Graphics;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

@SuppressWarnings("serial")

public class dibujaCuadrado extends JFrame implements ActionListener{

JButton boton;

JPanel panel;

public static void main(String[] args) {

dibujaCuadrado marco = new dibujaCuadrado();

marco.setSize(250, 350);

marco.setTitle("Dibuja rectangulo");

marco.dibujaGUI();

marco.setLocationRelativeTo(null);

marco.setVisible(true);

}

public void dibujaGUI() {

setDefaultCloseOperation(EXIT_ON_CLOSE);

Container ventana = getContentPane();

ventana.setLayout(new FlowLayout());

panel = new JPanel();

panel.setPreferredSize(new Dimension(230,280));

panel.setBackground(Color.white);

ventana.add(panel);

boton = new JButton("Haz click");

ventana.add(boton);

boton.addActionListener(this);

}

public void actionPerformed(ActionEvent evento) {

Graphics papel = panel.getGraphics();

papel.drawRect(10, 10, 100, 100);

papel.setColor(Color.cyan);

papel.fillRect(10, 10, 100, 100);

}

}