import javax.swing.JFrame;

import javax.swing.JComponent;

import java.awt.Toolkit;

import java.awt.Frame;

import java.awt.Dimension;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.geom.Rectangle2D;

import java.awt.Color;

public class SimpleFrameTest{

public static void main(String[] args){

JFrame frame = new JFrame();

MyComponent a = new MyComponent();

a.setBackground(Color.PINK);

frame.add(a);

frame.setSize(300,200);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true);

}

}

class MyComponent extends JComponent{

public void paintComponent(Graphics g){

Graphics2D g2 = (Graphics2D)g;

Rectangle2D rect = new Rectangle2D.Double(50,50,100,100);

g2.setPaint(new Color(123,200,50));

System.out.println(Color.RED);

g2.fill(rect);

}

}