EJB Remote vs Local deployment....difference???

[Pradeep Bhat]

what is the difference between deploying a stateless session bean with a remote and local interface.

This is my code :

  
package com.chapter1;

import javax.ejb.Local;
import javax.ejb.Remote;

@Remote
public interface HelloUser {
	public void sayHello(String message);
 }

 

  

package com.chapter1;

import javax.ejb.Stateless;

@Stateless (name="hhh")
public class HelloBeanImpl implements HelloUser {
	public void sayHello(String message) {
		System.out.println("\n-------------------------\n");
		System.out.println("Hello  " + message);
		System.out.println("\n-------------------------\n");
	}
}

 

I do the look up as
HelloUser user = (HelloUser)ctx.lookup("hhh/remote");

This works fine. But the same doesn't work for local interface.

  
package com.chapter1;

import javax.ejb.Local;
import javax.ejb.Remote;

@Local
public interface HelloUser {
	public void sayHello(String message);
 }

  

If i do the lookup as HelloUser user = (HelloUser)ctx.lookup("hhh/local");...i get the following exception

Exception in thread "main" javax.naming.NamingException: Could not dereference object [Root exception is java.lang.RuntimeException: Could not find InvokerLocator URL at JNDI address "hhh/local"; looking up local Proxy from Remote JVM?]
at org.jnp.interfaces.NamingContext.getObjectInstanceWrapFailure(NamingContext.java:1472)
at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:818)
at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:682)
at javax.naming.InitialContext.lookup(InitialContext.java:351)
at HelloWorldClient.main(HelloWorldClient.java:11)
Caused by: java.lang.RuntimeException: Could not find InvokerLocator URL at JNDI address "hhh/local"; looking up local Proxy from Remote JVM?
at org.jboss.ejb3.proxy.objectfactory.ProxyObjectFactory.createProxyFactoryProxy(ProxyObjectFactory.java:185)
at org.jboss.ejb3.proxy.objectfactory.ProxyObjectFactory.getObjectInstance(ProxyObjectFactory.java:146)
at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:304)
at org.jnp.interfaces.NamingContext.getObjectInstance(NamingContext.java:1447)
at org.jnp.interfaces.NamingContext.getObjectInstanceWrapFailure(NamingContext.java:1464)
... 4 more




If i do the look up as HelloUser user = (HelloUser)ctx.lookup("hhh"); ...i get the exception as

Exception in thread "main" java.lang.ClassCastException: org.jnp.interfaces.NamingContext
at HelloWorldClient.main(HelloWorldClient.java:11)




I am using jdk1.5 and jboss-5.0.1.GA.

[Jaikiran Pai]

what is the difference between deploying a stateless session bean with a remote and local interface.

Local interfaces are meant to be used from the same JVM as the application server on which your bean is deployed. Remote interfaces can be used from other (remote) JVMs too (example standalone clients).

Exception in thread "main" javax.naming.NamingException: Could not dereference object [Root exception is java.lang.RuntimeException: Could not find InvokerLocator URL at JNDI address "hhh/local"; looking up local Proxy from Remote JVM?]
at org.jnp.interfaces.NamingContext.getObjectInstanceWrapFailure(NamingContext.java:1472)
at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:818)
at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:682)
at javax.naming.InitialContext.lookup(InitialContext.java:351)
at HelloWorldClient.main(HelloWorldClient.java:11)

This shows that you are using a local interface from a remote JVM (standalone client). This is not allowed and hence the exception.