[jboss-user] [Beginners Corner] - NullPointerException at sun.reflect.NativeMethodAccessorImpl

[mhoennig]

Dear JBoss experts,

I tried my own "hello world" with EJB3 on JBoss 4.0.5GA today. But when I invoke a  method on my SLSB, I am getting this stack:

     [java] log4j:WARN No appenders could be found for logger (org.jboss.security.SecurityAssociation).
     [java] log4j:WARN Please initialize the log4j system properly.
[java] java.lang.NullPointerException
     [java]     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     [java]     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     [java]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     [java]     at java.lang.reflect.Method.invoke(Method.java:585)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:112)
     [java]     at org.jboss.ejb3.stateless.StatelessContainer.dynamicInvoke(StatelessContainer.java:263)
     [java]     at org.jboss.aop.Dispatcher.invoke(Dispatcher.java:106)
     [java]     at org.jboss.aspects.remoting.AOPRemotingInvocationHandler.invoke(AOPRemotingInvocationHandler.java:82)
     [java]     at org.jboss.remoting.ServerInvoker.invoke(ServerInvoker.java:828)
     [java]     at org.jboss.remoting.ServerInvoker.invoke(ServerInvoker.java:681)
     [java]     at org.jboss.remoting.transport.socket.ServerThread.processInvocation(ServerThread.java:358)
     [java]     at org.jboss.remoting.transport.socket.ServerThread.dorun(ServerThread.java:398)
     [java]     at org.jboss.remoting.transport.socket.ServerThread.run(ServerThread.java:239)
     [java]     at org.jboss.remoting.RemoteClientInvoker.invoke(RemoteClientInvoker.java:190)
     [java]     at org.jboss.remoting.Client.invoke(Client.java:525)
     [java]     at org.jboss.remoting.Client.invoke(Client.java:488)
     [java]     at org.jboss.aspects.remoting.InvokeRemoteInterceptor.invoke(InvokeRemoteInterceptor.java:55)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
     [java]     at org.jboss.aspects.tx.ClientTxPropagationInterceptor.invoke(ClientTxPropagationInterceptor.java:61)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
     [java]     at org.jboss.aspects.security.SecurityClientInterceptor.invoke(SecurityClientInterceptor.java:53)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
     [java]     at org.jboss.ejb3.remoting.IsLocalInterceptor.invoke(IsLocalInterceptor.java:77)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
     [java]     at org.jboss.ejb3.stateless.StatelessRemoteProxy.invoke(StatelessRemoteProxy.java:102)
     [java]     at $Proxy0.ping(Unknown Source)
     [java]     at ....EJB3TestClient.main(EJB3TestClient.java:38)

Does the log4j warning has to do with it?  Looking at the stack I doubt it.

My SLSB is pretty simple:

1. a remote interface:

package ...;
  | 
  | @javax.ejb.Remote
  | public interface EJB3StatelessTestSessionFacade
  | {
  | 	public String ping();
  | }
  | 

2. the bean:

package ...;
  | 
  | @javax.ejb.Stateless
  | public class EJB3StatelessTestSessionBean
  | 	implements EJB3StatelessTestSessionFacade
  | {
  | 	public String ping()
  | 	{
  | 		return "pong ";
  | 	}
  | }

3. a client:

package ...;
  | 
  | import java.util.Properties;
  | import javax.ejb.EJB;
  | import javax.naming.InitialContext;
  | 
  | public class EJB3TestClient
  | {
  | 	@EJB public static EJB3StatelessTestSessionFacade aFacade;
  | 	
  | 	/**
  | 	 * @param args
  | 	 */
  | 	public static void main(String[] args)
  | 	{
  | 		try 
  | 		{
  | 			Properties p = new Properties();
  | 			p.put("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");
  | 			p.put("java.naming.factory.url.pkgs","=org.jboss.naming:org.jnp.interfaces");
  | 			p.put("java.naming.provider.url","localhost:1099");
  | 			p.put("jnp.socket.Factory","org.jnp.interfaces.TimedSocketFactory");
  | 
  | 			System.out.println( "getting initial context" );
  | 			InitialContext aIC = new InitialContext(p);
  | 			
  | 			if ( aFacade == null )
  | 			{
  | 				System.out.println( "session bean lookup" );
  | 				aFacade = (EJB3StatelessTestSessionFacade) 
  | 					aIC.lookup( "java:ejb3test/EJB3StatelessTestSessionBean/remote" );
  | 			}
  | 			
  | 			System.out.println( "calling session bean" );
  | 			System.out.println( aFacade.ping() );
  | 		}
  | 		catch ( Exception aExc )
  | 		{
  | 			aExc.printStackTrace(System.err);
  | 		}
  | 	}
  | 
  | }

Any idea what I am doing wrong?

Thanks!
... Michael

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