Why @LocalBean is needed to deploy a EJB ?

[Himai Minh]

In NetBean, I have a web application called RoleBasedEJB.
I have a class like this :

//Only relevant parts shown:
//@LocalBean       
@Stateless
@Path("/students")
@DeclareRoles({"teacher", "student"})
public class StudentServiceImpl implements StudentService {
   
        @GET
	@Produces(MediaType.TEXT_XML)
        @RolesAllowed("teacher")
        @Path("/{studentId}")	
	public String getStudent(@PathParam("studentId") String strStudentId) throws Exception {....}

public class StudentApplication extends Application {
   
   private Set<Object> singletons = new HashSet<Object>();
   private Set<Class<?>> s = new HashSet<Class<?>>();

   public StudentApplication() {
      s.add( StudentServiceImpl.class);
   }

   @Override
   public Set<Class<?>> getClasses() {
      return s;
   }

   @Override
   public Set<Object> getSingletons() {
      return singletons;
   }
}

//web.xml
<web-app>
  <display-name>REST Student Service</display-name>

  <servlet>
    <servlet-name>Jersey Service</servlet-name>
    <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
    <init-param>
       <param-name>javax.ws.rs.Application</param-name>
       <param-value>StudentApplication</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  
   
  <servlet-mapping> 
    <servlet-name>Jersey Service</servlet-name>
     <url-pattern>/rest/*</url-pattern>
  </servlet-mapping>
  <security-constraint>
       <web-resource-collection> 
           <web-resource-name>Role base application</web-resource-name>
           <url-pattern>/rest/*</url-pattern>
           <http-method>GET</http-method>
        </web-resource-collection>    
       <auth-constraint>
           <role-name>teacher</role-name>
           <role-name>student</role-name>
       </auth-constraint>    
    </security-constraint>
    <login-config>
         <auth-method>BASIC</auth-method>
    </login-config>  
     <security-role>
        <role-name>teacher</role-name>
      </security-role>  
       <security-role>
         <role-name>student</role-name>
      </security-role>
   </web-app> 

Client side:

//only relevant parts shown:
public class StudentClient {
 
  public static void main(String[] argv) {
                Authenticator.setDefault(new SimpleAuthenticator("john", "secret"));
 	        try {
			 if ("Get_Student".equalsIgnoreCase(argv[0])) {
                            Client client = Client.create();
                             client.addFilter(new LoggingFilter());
 
        WebResource resource = client.resource("http://localhost:8080/RoleBasedEJB/rest/");
        Student response = resource.path("/students/13005529").accept("text/xml").get(new GenericType<Student>(){});
         System.out.println("Get_Student: response=" + response);
 	}

When the @LocalBean is commented out in the resource root class, Glassfish gives me this error when the client tried to access the resource using credentials john/secret.

WARNING: StandardWrapperValve[Jersey Service]: PWC1406: Servlet.service() for servlet Jersey Service threw exception
java.lang.IllegalArgumentException: object is not an instance of declaring class
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
	at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185)
	at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
	at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:288)
	at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
	at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
	at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
	at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
	at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1469)
	at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1400)
	at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1349)
	at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1339)
	at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
	at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
	at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:708)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:770)
	at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1550)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
	at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
	at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
	at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
	at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
	at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
	at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
	at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:757)
	at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1056)
	at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:229)
	at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
	at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
	at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
	at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
	at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
	at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
	at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
	at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
	at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
	at java.lang.Thread.run(Thread.java:619)

Why @LocalBean is important in this case?

[Frits Walraven]

An EJB with a remote view is not required to be supported as a JAX-RS resource. I am not sure what kind of annotation you have on your StudentService (@Remote maybe?).

Adding the @LocalBean makes the EJB have a local view and that has to be supported by JAX-RS.

Regards,
Frits

[Himai Minh]

Thanks for your reply.
Before, the StudentService interface did not have any annotation. Now, I put @Remote in this:

//Only relevant part shown
@Remote
public interface StudentService {
       public String getStudent(String strStudentId) throws Exception;
}

The implementation resource root class, StudentServiceImpl has @LocalBean, @Stateless and @DeclaredRoles.

It works the same after I put @Remote in the StudentService interface.

Does it mean all JAX-RS resource root class must be annotated with @LocalBean if it is deployed as @Stateless or @Singleton?

[Frits Walraven]

Yes, or put @Local in the StudentService interface.