import javax.swing.*;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.*;
import java.awt.BasicStroke;

public class StrokeTest3 extends JPanel{

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

    StrokeTest3 app = new StrokeTest3();
    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;

    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, 
                        RenderingHints.VALUE_ANTIALIAS_ON);

    BasicStroke joinStroke
      = new BasicStroke(20.0f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL);
    g2.setStroke(joinStroke);

    GeneralPath polygon = new GeneralPath();
    polygon.moveTo(20, 150);
    polygon.lineTo(50, 50);
    polygon.lineTo(80, 150);
    g2.draw(polygon);

    polygon.reset();

    BasicStroke miterStroke
      = new BasicStroke(20.0f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER);
    g2.setStroke(miterStroke);

    polygon.moveTo(120, 150);
    polygon.lineTo(150, 50);
    polygon.lineTo(180, 150);
    g2.draw(polygon);

    polygon.reset();

    BasicStroke roundStroke
      = new BasicStroke(20.0f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND);
    g2.setStroke(roundStroke);

    polygon.moveTo(220, 150);
    polygon.lineTo(250, 50);
    polygon.lineTo(280, 150);
    g2.draw(polygon);
  }
}