EJB: Method invocation and interfaces - ejb

Question

I'm currently upgrade our business javaee environment. A new feature should be implemented which allows to manage maintenance notifications in the webframework that affect other web applications on the same server. The notifications should be transferred using EJB (either the framework send them to the application or the application asks for them).
I tried to implement it based on interfaces. The interfaces are used in the method signatures and the conctret implementations of those interfaces are only known by the webframework respectively the applications.
But all invocations fail with either a ClassNotFoundException (when the framwork sends the notification to the application) or a ClassCastException (when the application ask for new maintenances).
The question: Is it impossible to implement this using interfaces? Do I always need the concret implementations on both sides? The preceeding EJB lookup does work using interfaces (#Remote annotation), so why do I have those exceptions?
Thanks in advance!
I will give you a short overview over my classes so you have more information about what I'm doing:
Interface: IMaintenanceInfo:
This interface will be used for the EJB method invocations and contains the information about a single maintenance.
Interface: IRemoteMaintenanceEJB:
This interface is the #Remote interfaces for the RemoteMaintenanceEJB. This is used by the applications to ask for new maintenances.
Interface: IApplicationEJB:
This interface is used to receive maintenance notifications from the webframework. It is #Remote.
Class: MaintenanceInfoImpl:
This class implements IMaintenanceInfo
Class: RemoteMaintenanceEJBImpl:
This class implements IRemoteMaintenanceEJB
Class: ApplicationEJBInfo:
This class implements IApplicationEJB
When the RemoteMaintenanceEJBImpl sends a MaintenanceInfoImpl to an ApplicationEJBImpl, the following method will be used:
public interface IApplicationImpl {
public void announceMaintenance(IMaintenanceInfo maintenanceInfo);
}
The invocation
remoteApplication.announceMaintenance(new MaintenanceInfoImpl(date/*, ...*/))
Failes with a ClassNotFoundException on the application side as it tries to find the MaintenanceInfoImpl which is only available on the webframework side.
Caused by: java.lang.ClassNotFoundException: package.webapp.wf.framework.MaintenanceInfoImpl from [Module "deployment.CommonDBFrontend.war:main" from Service Module Loader]
at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:190)
at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:468)
at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:456)
at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:398)
at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:120)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at org.jboss.marshalling.cloner.ClassLoaderClassCloner.clone(ClassLoaderClassCloner.java:49)
at org.jboss.marshalling.cloner.SerializingCloner.clone(SerializingCloner.java:157)
at org.jboss.marshalling.cloner.SerializingCloner.clone(SerializingCloner.java:134)
at org.jboss.marshalling.cloner.SerializingCloner.clone(SerializingCloner.java:186)
at org.jboss.marshalling.cloner.SerializingCloner.clone(SerializingCloner.java:134)
at org.jboss.as.ejb3.remote.LocalEjbReceiver.clone(LocalEjbReceiver.java:267)
Which again raises this exception (JBoss AS 7.1.2)
java.lang.RuntimeException: JBAS014154: Failed to marshal EJB parameters
When the ApplicationEJBImpl asks the RemoteMaintenanceEJBImpl for new maintenances, the following method will be used:
public interface IRemoteMaintenanceEJB {
pubilc List<IMaintenanceInfo> getMaintenances();
}
The invocation failes with the exception
Caused by: java.lang.ClassCastException: package.webapp.wf.framework.MaintenanceInfoImpl cannot be cast to package.webapp.ejb.IMaintenanceInfo
at package.webapp.ejb.impl.ApplicationEJBImpl.announceMaintenance(ApplicationEJBImpl.java:187)
at package.webapp.ejb.impl.ApplicationEJBImpl.initialize(ApplicationEJBImpl.java:96)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_11]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_11]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_11]
at java.lang.reflect.Method.invoke(Unknown Source) [rt.jar:1.7.0_11]
...

Answer 1

implement java.io.Serializable for the class MaintenanceInfoImpl
and also make sure you set serialVersionUID for the same.