java.net.SocketTimeoutException: Receive timed out

这几天学习了一下EJB，刚开始搭建环境，配置JBOSS服务器后，创建第一个无状态会话Bean( stateless Session bean)HelloWord，运行客户端连接时报异常：java.net.SocketTimeoutException: Receive timed out。

下面是我的ejb client:

package com.ejb.junit;

import java.util.Properties;

import javax.naming.InitialContext;
import javax.naming.NamingException;

import com.ejb.HelloWorldRemote;

public class EJBTest {
	public static void main(String[] args) {
		Properties prop=new Properties();
		prop.setProperty("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");
		prop.setProperty("java.nameing.provider.url", "jnp://127.0.0.1:1099");
		prop.setProperty("java.naming.factory.url.pkgs", "org.jboss.naming:org.jnp.interfaces");
		
//		prop.setProperty(InitialContext.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
//		prop.setProperty(InitialContext.PROVIDER_URL, "jnp://127.0.0.1:1099");
//		prop.setProperty(InitialContext.URL_PKG_PREFIXES, "org.jboss.naming:org.jnp.interfaces");
		
		
		try {
			InitialContext ctx=new InitialContext(prop);
			HelloWorldRemote helloworld=(HelloWorldRemote)ctx.lookup("HelloWorld/remote");
			System.out.println(helloworld.sayHello("World"));
			System.out.println(helloworld.sayHello("China"));
		} catch (NamingException e) {
			e.printStackTrace();
		}
	}
}

 运行时异常堆栈如下：

javax.naming.CommunicationException: Receive timed out [Root exception is java.net.SocketTimeoutException: Receive timed out]
	at org.jnp.interfaces.NamingContext.discoverServer(NamingContext.java:1690)
	at org.jnp.interfaces.NamingContext.checkRef(NamingContext.java:1812)
	at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:695)
	at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:688)
	at javax.naming.InitialContext.lookup(InitialContext.java:392)
	at com.ejb.junit.EJBTest.main(EJBTest.java:28)
Caused by: java.net.SocketTimeoutException: Receive timed out
	at java.net.PlainDatagramSocketImpl.receive0(Native Method)
	at java.net.PlainDatagramSocketImpl.receive(PlainDatagramSocketImpl.java:145)
	at java.net.DatagramSocket.receive(DatagramSocket.java:725)
	at org.jnp.interfaces.NamingContext.discoverServer(NamingContext.java:1659)
	... 5 more

 网上找了好些方法都没法解法，最后在一个网站上看着直接用类的常量来代替，就是将上面绿字注释去掉，三行红字打上注释后，居然奇迹般的运行正常了。。真是让我费解，如果大家碰到这种问题，可以试下这个方法。我把类的常量打印出来，跟上面的是一样的，哎，想不明白，如果有知道问题答案或是有解决办法的高人的话，还请指点在下。。。