为什么执行结果是这个样子_JDK1.7

package com.practice.test;
import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
import java.awt.geom.Ellipse2D.Double;

import javax.swing.*;
/**
 * 测试字体相关
 * @author KangMing
 * @version 1.7 2014-09-03
 */
public class FontTest {
	public static void main(String[] args){
		EventQueue.invokeLater(new Runnable(){
			public void run(){
				FontFrame frame = new FontFrame();
				frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
				frame.setVisible(true);
			}
		});
		
	}
}
/**
 * A frame with a text message component
 *
 */
class FontFrame extends JFrame{
	public FontFrame(){
		setTitle("FontTest");
		setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
		
		//将组件加到框架中
		FontComponent component = new FontComponent();
		add(component);		
	}
	
	public static final int DEFAULT_WIDTH = 300;
	public static final int DEFAULT_HEIGHT = 200;
}

class FontComponent extends JComponent{
	public void FontComponent(Graphics g){
		Graphics2D g2 = (Graphics2D) g;
		
		String message = "Hello World!";
		
		Font f = new Font("Serif", Font.BOLD, 36);
		g2.setFont(f);
		
		//measure the size of the message
		
		FontRenderContext context = g2.getFontRenderContext();
		Rectangle2D bounds = f.getStringBounds(message, context);
		
		//set(x, y) = top - left corner of text
		
		double x = (getWidth() - bounds.getWidth()) / 2;
		double y = (getHeight() - bounds.getHeight()) / 2;
		
		//add ascent to y to reach the baseline
		
		double ascent = -bounds.getY();
		double baseY = y + ascent;
		
		//draw the message
		
		g2.drawString(message, (int) x, (int) baseY);
		g2.setPaint(Color.LIGHT_GRAY);
		
		//draw the baseline
		
		g2.draw(new Line2D.Double(x, baseY, x + bounds.getWidth(),baseY));
		
		//draw the enclosing rectangle
		
		Rectangle2D rect = new Rectangle2D.Double(x, y, bounds.getWidth(),bounds.getHeight());
		g2.draw(rect);
		
	}
}

public void FontComponent(Graphics g)

public void FontComponent(Graphics g)

public void paintComponent(Graphics g)