javax.ejb.EJBException：嵌套异常是：java.rmi.UnmarshalException：找不到方法：'helloWorld（Ljava.lang.Long; Ljava.util.List;）'

Question

Getting the exception while running my EJB3 application on weblogic (10.2)

javax.ejb.EJBException: nested exception is: java.rmi.UnmarshalException: Method not 
found: 'helloWorld(Ljava.lang.Long;Ljava.util.List;)'

I created a method as exact copy of what is there that works. However this very method didn't work.

My Business Interface has the following definition

  public abstract interface MySession {
  // .. some other methods here, which works fine
  /**
   * Returns .... something
   *
   * @param theId ...
   *
   * @throws MyException If ...something happens
   *
   * @ejb.interface-method
   */
    public String helloWorld(Long theId, List<String>list) throws MyException;

My Bean implementation class

 @Stateless(mappedName="ejb.TaxSession")
 @Remote(TaxSession.class)
 public  class MySessionEJB implements MySession {
      @javax.persistence.PersistenceContext(unitName="myDS")
      private EntityManager m_SCSentityManager ;

      //.. some methods that work ... (defined in a same fashion as the bad one ..
    /**
 * Returns tax details from tblDiscreteTaxcollected by BillID
 *
 * @param theId ...
 *
 * @throws MyException If something wrong..
 *
 * @ejb.interface-method
 */
  public String helloWorld(Long theId, List<String>list) throws MyException{
     String returnValue = "Hello world !!" ;

     return returnValue ;
  }

 }

And here is a client code (JUnit 4):

 @Test
public final void taxesByWtns() {
System.out.println("Test taxation started...");
long theId= 1111222;

List<String> theList= new ArrayList<String>();
theList.add("test1");
theList.add("test2");
theList.add("test3");

try {
    System.out.println(getTaxSession().helloWorld(theId, theList));

} catch (MyException e) {
    System.out.println("EXCEPTION HAS OCCURED !!") ; 
    e.printStackTrace();
} catch (NamingException e) {
    System.out.println("EXCEPTION HAS OCCURED !!") ;
    e.printStackTrace();
}
}

I check the ear file, and see that method is there. Before this, my method had "long" instead of "Long" in a first parameter, and in ear file, I could only see 2nd parameter. I gathered it has something to do with serialization.. so I changed to Long - and now both parameters appear (in ear file). However, exception abot "Method Not found.." still comes up..

Where is the pitfall? (I installed, updated and re-installed the deployment few times, as suggested in the similar post - to no avail :( )

Thanks

Answer 1

Could be a problem with the MyException type. Be sure to have the MyException type available at client and server side and that it meets the requirenments for remote invocations (Serializable).

Another problem is that the remote interface is of type TaxSession and not MySession.

@Stateless(mappedName="ejb.TaxSession") @Remote(TaxSession.class) --> not MySession

but

 public  class MySessionEJB implements MySession

Are you sure that you provide the right remote interface which owns the method declared within the MySession interface. Check the server logs for EJB deployment outputs.

Answer 2

I solved the issue. Here are details, if someone should run into the same problem

In my code, I used generics !!

public String helloWorld(Long theId, List<String>list) throws MyException{}

Once, I removed that - it started working OK. Don't know what is the theoretical concept behind it, but it worked !!