请各位大侠指点小弟关于socket通信问题

Question

server服务端程序如下
import java.io.*;
import java.net.*;
public class severa
{
static public void main(String args[]) throws IOException
{
ServerSocket sersoc=null;
Socket soc=null;
DataInputStream in =null;
PrintStream out=null;
InetAddress clientIP=null;
String str=null;
try{
sersoc=new ServerSocket(8000);
soc=sersoc.accept();
in=new DataInputStream(soc.getInputStream());
out=new PrintStream(soc.getOutputStream());
clientIP=soc.getInetAddress();
System.out.println("clent's IP address"+clientIP);
out.println("welcome......");
    str=in.readLine(); 
    while(!str.equals("quit"))
    {
     System.out.println("client said:"+str);
     str=in.readLine();  
        
    
    
    } 
    //System.out.println(str);
    System.out.println("client want to leave");
    }
    catch(Exception e)
    {
     System.out.println("Error:"+e);
    }
    finally
    {
     in.close();
     out.close();
     soc.close();
     sersoc.close();
     System.exit(0);
    }
}
}
客户端程序如下
import java.net.*;
import java.io.*;
public class client 
{
static public void main(String args[]) throws IOException 
{
Socket soc=null;
DataInputStream in=null;
PrintStream out=null;
DataInputStream sysin=null;
String strin=null;
String strout=null;
InetAddress name;
try
{
//args[0]="local host";
name=InetAddress.getByName(null);
soc=new Socket(name,8000);//name为服务器名字
System.out.println("connecting to the server   ");
//System.out.println("connecting to the server   ");
in=new DataInputStream(soc.getInputStream());
out=new PrintStream(soc.getOutputStream());
strin=in.readLine();
System.out.println("server said:"+strin);
sysin=new DataInputStream(System.in);
strout=sysin.readLine();
while(!strout.equals("quit"));
{
out.println(strout);
strout=sysin.readLine();

}
out.println(strout); 
 


}

catch(Exception e)
{
System.out.println("Error:"+e);
}
finally{
in.close();
out.close();
sysin.close();
soc.close();
System.exit(0);
}


}
}
请问各位大侠 我的程序怎么不能相互通信呀?但能运行,运行完事就没反映了,你往里面输入数据服务端根本得不到