import javax.swing.*;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.*;
import java.awt.Color;
import java.awt.RadialGradientPaint;
import java.awt.MultipleGradientPaint;

public class PaintTest7 extends JPanel{

  public static void main(String[] args){
    JFrame frame = new JFrame();

    PaintTest7 app = new PaintTest7();
    frame.getContentPane().add(app);

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setBounds(10, 10, 300, 200);
    frame.setTitle("ƒ^ƒCƒgƒ‹");
    frame.setVisible(true);
  }

  public void paintComponent(Graphics g){
    Graphics2D g2 = (Graphics2D)g;

    float[] dist = {0.0f, 0.4f, 1.0f};
    Color[] colors = {Color.RED, Color.WHITE, Color.BLUE};

    RadialGradientPaint gradient = new RadialGradientPaint(
        100.0f, 80.0f, 
        60.0f,
        dist,
        colors,
        MultipleGradientPaint.CycleMethod.NO_CYCLE
        // MultipleGradientPaint.CycleMethod.REFLECT
        // MultipleGradientPaint.CycleMethod.REPEAT
    );
    g2.setPaint(gradient);

    g2.fill(new Rectangle2D.Double(20, 20, 200, 130));
  }
}