udp实现数据传输,如何老有有关问题 请指点下

udp实现数据传输,怎么老有问题 请指点下
服务器端:
import   java.net.*;
public   class     ServerUdp
{
public   static   void   main(String[]   args)  
{try   {byte[]buff=new   byte[256];
InetAddress   address   =   InetAddress.getByName( "127.0.0.1 ");
              System.out.println( "Checking   at:   "   +   address);
           
          DatagramSocket   socket=new   DatagramSocket(8000);
  DatagramPacket   topacket=new   DatagramPacket(buff,buff.length,address,8000);
  System.out.println( "Server   started ");
          socket.receive(topacket);  

    System.out.println( "received! ");
}catch(Exception   e){System.out.println( "Not   received! ");}
}

  }
客户端(发送数据)
import   java.net.*;
class   ClientUdp  
{
public   static   void   main(String[]   args)  
{     try{
InetAddress   address   =   InetAddress.getByName( "127.0.0.1 ");
              System.out.println( "Checking   at:   "   +   address);
           

DatagramSocket   socket=new   DatagramSocket(8000);
        byte[]buff=new   byte[256];
                String   str= "-help ";
buff=str.getBytes();
DatagramPacket   frompacket=new   DatagramPacket(buff,buff.length,address,8000);
                System.out.println( "translating.. ");
socket.send(frompacket);
                System.out.println( "pass ");
      }catch(Exception   e){   System.out.println( "error! ");
      e.printStackTrace();
      }
    }
}
是不绑定的问题?
怎么解决

------解决方案--------------------
你没说是什么问题啊? 唯一的带有问号的那一句还特别奇怪.