java.net.BindException: Address already in use: JVM_Bind

import java.net.*;
import java.io.*;
public class Server {
        public static void main(String[] args) {
         
                ServerSocket server=null;
                try{
                        server=new ServerSocket(8888);  //x1                                                        System.out.println("服务器套接字已经被创建");
                        while(true){  
                                System.out.println("等待客户机");
                                Socket newSocket=server.accept();//x2
                                System.out.println("已与客户机连接");
                        }
                }catch(IOException ie)
                {
                        System.out.println(ie);
                }finally{
                        try
                        {
                            if(server!=null) server.close();//x3
                        }catch(IOException ie){}
                }
        }

}