j2ee 1.4 app server问题，高手有请!

[yanyanyan]

我把一个session bean deploy到j2ee 1.4 app server上,但客服端访问时出错。
客服端代码如下：
Context ctx=new InitialContext();
Object obj = ctx.lookup("BillingHome");
BillingHome Home = (BillingHome)javax.rmi.PortableRemoteObject.narrow(obj,BillingHome.class);
错误如下：
Exception in thread "main" javax.naming.NoInitialContextException: Need to specify class name in environment or system property, or as an applet parameter, or i
n an application resource file: java.naming.factory.initial
at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:640)
at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:243)
at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java:280)
at javax.naming.InitialContext.lookup(InitialContext.java:347)
at examples.EJBClient.main(EJBClient.java:20)
j2ee1.3好像不需指明jndi工厂类，看来1.4有变化，不知那位知道该jndi工厂类是哪个?