程序调试问题,"找不到符号"!
我用的版本是jdk1.6.0_02。下面是我从《JAVA2核心技术》上抄的一个例子，是用JCreator编译的，结果有个这样的问题，见注释。帮忙看看。
import   java.awt.*;
import   java.awt.geom.*;
import   java.util.*;
import   java.awt.event.*;
import   javax.swing.*;

public   class   Sketch
{
public   static   void   main()
{
SketchFrame   frame   =   new   SketchFrame();
frame.setDefaultOperation(EXIT_ON_CLOSE);//找不到符号
frame.setVisible(true);
}
}

class   SketchFrame   extends   JFrame
{
public   SketchFrame()
{
setTitle( "Sketch ");
setSize(W,H);

SketchPanel   panel   =   new   SketchPanel();
add(panel);
}
private   final   static   int   W   =   300;
private   final   static   int   H   =   200;
}

class   SketchPanel   extends   JPanel
{
private   Point2D   last;
private   ArrayList <Line2D>   lines;

public   SketchPanel()
{
last   =   new   Point2D.Double(100,100);
lines   =   new   ArrayList <Line2D> ();
KeyHandler   listener   =   new   KeyHandler();
addKeyListener(listener);
setFocusable(true);
}

public   void   add(int   dx,int   dy)
{
Point2D   end   =   new   Point2D.Double(last.getX()+dx,last.getY()+dy);
Line2D   line   =   new   Line2D.Double(last,end);
lines.add(line);
repaint();

last   =   end;
}
public   void   paintComponent(Graphics   g)
{
super.paintComponent(g);
Graphics2D   g2   =   (Graphics2D)g;

for(Line2D   l:lines)
{
g2.draw(l);
}
}

private   static   final   int   SMALL_INCREMENT   =   1;
private   static   final   int   LARGE_INCREMENT   =   5;

private   class   KeyHandler   implements   KeyListener
{
public   void   keyPressed(KeyEvent   e)
{
int   KeyCode   =   event.getKeyCode();//找不到符号

int   d;
if(event.isShiftDown())//找不到符号
d   =   LARGE_INCREMENT;
d   =   SMALL_INCREMENT;

if(KeyCode   ==   KeyEvent.VK_RIGHT)   add(-d,0);
if(KeyCode   ==   KeyEvent.VK_LEFT)   add(d,0);
if(KeyCode   ==   KeyEvent.VK_UP)   add(0,-d);
if(KeyCode   ==   KeyEvent.VK_DOWN)   add(0,d);
}
public   void   keyReleased(KeyEvent   event){}

public   void   keyTyped(KeyEvent   event)
{
char   keyChar   =   event.getKeyChar();

int   d;
if(Character.isUpperCase(keyChar))
{
d   =   LARGE_INCREMENT;
keyChar   =   Character.toLowerCase(keyChar);
}
else
d   =   SMALL_INCREMENT;

if(keyChar   ==   'h ')   add(-d,0);
else   if(keyChar   ==   'l ')   add(d,0);
else   if(keyChar   ==   'k ')   add(0,-d);
else   if(keyChar   ==   'j ')   add(0,d);
}
}
}

------解决方案--------------------