import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Composite;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class MainClass extends JPanel {
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
RenderingHints rh = g2.getRenderingHints();
rh.put(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2.setRenderingHints(rh);
int x = 40, y = 40;
g.setColor(Color.red);
g.fillOval(x, y, 50, 50);
Composite old = g2.getComposite();
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER));
g.setColor(Color.green);
g.fillOval(x + 30, y + 30, 30, 30);
g2.setComposite(old);
g.setColor(Color.black);
g.drawString("AlphaComposite.SRC_OVER", x, y + 80);
}
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.getContentPane().add(new MainClass());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(200, 200);
frame.setVisible(true);
}
}