tomcat下使用rmi出错了

[Technology_What]

在我的项目工程中写了一个rmi服务，并用一个servlet调用它，就是在tomcat启动时，这个rmi服务就启动了
但是在这个tomcat启动时，报错了，不知道是什么原因 希望大家帮忙看看，谢谢了。

错误如下图



RMIRunner 类如下：

package server;

import   java.rmi.*;
import   java.rmi.registry.*;
import   javax.naming.*;
import   org.apache.log4j.Logger;

public   class   RMIRunner   implements   Runnable   {
       
        private   static   Logger   log   =   Logger.getLogger(   RMIRunner.class   );
        private   void   rmiStart()
        {
            try   
            {
            	System.out.println("11111111111111111");  
            	System.setProperty("java.rmi.server.hostname", "172.21.15.185");  
            	
            	LocateRegistry.createRegistry(1099);  
            	
            	System.out.println("222222222222222222222");
        		GetResult gr_server = new GetResultImpl("service"); 


        		Context namingContext = new InitialContext();
        		
        		System.out.println("3333333333333333333333");   
        		
        	//	namingContext.rebind("coming_server", gr_server);  
        		
        		namingContext.rebind("rmi://172.21.15.185:1099/coming_server", gr_server);  
        	//	namingContext.rebind("rmi://localhost:1099/ss", c);   
        	    System.out.println("444444444444444444444444444"); 
                log.info( "rmiStart   successful. ");
        		
                System.out.println("the server is ready! yes!") ;
                    
            }   
            catch   (Exception   e)   
            {
                    log.error( "During   rmiStart ",   e);
            }
          }
       
        public   void   run()   
        {
                rmiStart();
        }
       
}

将这条语句namingContext.rebind("rmi://172.21.15.185:1099/coming_server", gr_server);
换成namingContext.rebind("coming_server", gr_server); 时，tomcat启动时不会报错，但是用客户端启动时，出现找不到coming_server
错误如下：javax.naming.NameNotFoundException:coming_server

package server;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.GenericServlet;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class RMIInit extends GenericServlet {

	/**
	 * Constructor of the object.
	 */
	public RMIInit() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}


	public void init() throws ServletException {        
		RMIRunner   rmiRunner   =   new   RMIRunner();
        Thread   t   =   new   Thread(rmiRunner);
        t.start();
		// Put your code here
	}

	
	public void service(ServletRequest arg0, ServletResponse arg1)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		
	}

}