java 问题（疯了）

import java.applet.* ;
import java.awt.* ;
import java.awt.event.* ;
public class Exam3_2 extends Applet implements ActionListener,MouseListener
{
private Button But;
String str;
String mouseClickCnt="单击"
Dimension CurrentPos=new Dimension();
int clickCnt=0;
public void init()
{
But=new Button("按钮");
serLayout(new FlowLayout());
add(But);
But.addActionListener(this);
addMouseListener(this);
}
public void paint(Graphics g)
{
str=new String("单击了"+clickCnt+"次按钮"）；
g.drawString(str,10,20);
g.drawString("鼠标"+mouseClickCnt+"位置:)"+currentPos.width+","+currentPos.height+")",10,70);
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource==But)
{
clickCnt++;
repaint();
}