RMI & Spring ends up on ClassCastException on client - spring

Question

I wrote a simple client server architecture that helps me producing PDF files out of MS Office documents. The communication is handled via RMI and Spring wraps the entire complexity on the server side.
I cannot use Spring on the client side, because I call the methods from Matlab 2007b. A Jar with dependencies to spring produces exceptions due to the special handling of static and dynamic classpaths in Matlab.
Long story short: I wrote a simple RMI client in plain java:
import com.whatever.PDFCreationService;
Object service = Naming.lookup("rmi://operations:1099/pdfCreationService");
System.out.println((PDFCreationService)service); //produces ClassCastException
Interface:
public interface PDFCreationService {
public PDFCreationConfig createPDF(PDFCreationConfig config) throws IOException, InterruptedException, OperationInterruptionException;
}
Extracted out of my "former" spring config (client side):
<bean id="pdfCreationService" class="org.springframework.remoting.rmi.RmiProxyFactoryBean">
<property name="serviceUrl" value="rmi://operations:1099/pdfCreationService"/>
<property name="serviceInterface" value="com.whatever.creator.PDFCreationService"/>
</bean>
and on the server side :
<bean class="org.springframework.remoting.rmi.RmiServiceExporter">
<property name="serviceName" value="pdfCreationService"/>
<property name="service" ref="pdfCreationService"/>
<property name="serviceInterface" value="com.whatever.creator.PDFCreationService"/>
<!-- defaults to 1099 -->
<property name="registryPort" value="1099"/>
</bean>
When I run the code the following exception is thrown:
Exception in thread "main" java.lang.ClassCastException: $Proxy0 cannot be cast to com.whatever.creator.PDFCreationService
I am 100% sure that I do not try to cast to a class like in this post: "ClassCastException: $Proxy0 cannot be cast" error while creating simple RMI application
Does spring encapsulate my interface in a different interface? Is there a way to find out which interface the Proxy hides?
Please let me know if you need more details to clarify my issue.

Answer 1

The RmiServiceExporter exports a RmiInvocationHandler if the remote service don't implements Remote, (ie, not is a traditional RMI Server)
If you can't use a RmiProxyFactoryBean in the client side, that is a bean factory for service interface proxies that convert service calls to RemoteInvocations, seems better option to use traditional RMI instead.
You can use the RmiServiceExporter to export tradional RMI Services too, like
public interface PDFCreationService extends Remote {
public PDFCreationConfig createPDF(PDFCreationConfig config) throws RemoteException;
}