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

public class StrokeTest2 extends JPanel{

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

    StrokeTest2 app = new StrokeTest2();
    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 buttStroke
      = new BasicStroke(25.0f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER);
    g2.setStroke(buttStroke);

    g2.draw(new Line2D.Double(50, 30, 230, 30));

    BasicStroke roundStroke
      = new BasicStroke(25.0f, BasicStroke.CAP_ROUND, BasicStroke.JOIN_MITER);
    g2.setStroke(roundStroke);

    g2.draw(new Line2D.Double(50, 80, 230, 80));

    BasicStroke squareStroke
      = new BasicStroke(25.0f, BasicStroke.CAP_SQUARE, BasicStroke.JOIN_MITER);
    g2.setStroke(squareStroke);

    g2.draw(new Line2D.Double(50, 130, 230, 130));

/*
    BasicStroke normalStroke = new BasicStroke(2.0f);
    g2.setStroke(normalStroke);
    g2.setPaint(Color.WHITE);

    g2.draw(new Line2D.Double(50, 30, 230, 30));
    g2.draw(new Line2D.Double(50, 80, 230, 80));
    g2.draw(new Line2D.Double(50, 130, 230, 130));
*/
  }
}