Avoiding WARNING: Hessian/Burlap: <class> is an unknown class in WebappClassLoader

Question

I'm using Spring and Hessian together in this project with Tomcat as its container. All the Hessian codes work properly (the data is sent and saved without any hitches) but there is this thing that keeps getting logged into the catalina.out

Sep 12, 2013 1:49:49 PM com.caucho.hessian.io.SerializerFactory getDeserializer
WARNING: Hessian/Burlap: 'com.manilapath.mppiservices.document.impl.DocumentInternal' is an unknown class in WebappClassLoader
  context: /articleservices
  delegate: false
  repositories:
----------> Parent Classloader:
ClassRealm[plugin>org.apache.tomcat.maven:tomcat7-maven-plugin:2.0-SNAPSHOT, parent: sun.misc.Launcher$AppClassLoader@3f611aec]
:
java.lang.ClassNotFoundException: com.manilapath.mppiservices.document.impl.DocumentInternal

I am somewhat worried that this will either bloat the logs or cause some problem along the road. Note that the "DocumentInternal" class is the class I'm using to pass data to the Hessian service and it is actually being deserialized correctly. I've been poking around the internet for a few days now looking for a lead into this warning but I still can't trace it, does anyone have any hints where I could look?

Answer 1

This warning appears when a class included into the Hessian stub has a sub-class that is not included in the Hessian stub. At least that's how it is in my case. Removing unneeded extensions caused about by bad use of inheritance solved this problem.

Answer 2

What helped me to turn this WARNING off is to add one line at the end of the ${tomcat_home}/conf/loggin.properties:

com.caucho.hessian.io.SerializerFactory.level = SEVERE