import java.awt.Color;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main extends JPanel {
public void paint(Graphics g) {
super.paint(g);
Graphics2D g2d = (Graphics2D) g;
GradientPaint gp1 = new GradientPaint(5, 5, Color.red, 20, 20, Color.yellow, true);
g2d.setPaint(gp1);
g2d.fillRect(20, 20, 300, 40);
}
public static void main(String[] args) {
JFrame frame = new JFrame("GradientsRedYellow");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new Main());
frame.setSize(350, 350);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}