请问为什么这段程序中定义Timer的那句话会报错?


package my.pong;
import javax.swing.*;
import java.awt.*;
import java.awt.Label;
import java.util.Timer;.....      //中间的部分都省略    public static void main(String args[]) {
             javax.swing.Timer   mytimer=new   javax.swing.Timer(1,new   ActionListener(){    /*就是这句话报错,说can not find symbol
                                                                                                symbol: class ActionListener
                                                                                                location: my.pong.Pong*/
                    public   void   actionPerformed(ActionEvent   e) 
                    { 
                        int x,y;
                        x=ball.getBounds().x;
                        y=ball.getBounds().y;
                        x=x+1;
                        y=y+1;
                        ball.setLocation(x,y);
                     }                      }); 
        mytimer.start();
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Pong().setVisible(true);
           
            }
        });
    }
    
    // 变量声明 - 不进行修改                     
    private java.awt.Label ball;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private java.awt.Label player1;
    private java.awt.Label player2;
    // 变量声明结束                   
    
}请问错在哪里?是一开始少import了什么东西吗?