Any Idea why it would occur ?
Here it the exception stack trace.
Caused by: java.lang.ClassCastException
at org.jboss.persistence.jbossdo.schema.JDOResolvedComplexType.getAssocationByName(JDOResolvedComplexType.java:132)
at org.jboss.persistence.jbossdo.schema.JDOSchemaBuilder.resolveAssociations(JDOSchemaBuilder.java:177)
at org.jboss.persistence.jbossdo.schema.JDOSchemaBuilder.buildSchema(JDOSchemaBuilder.java:44)
at org.jboss.persistence.jbossdo.PersistenceManagerFactoryImpl.(PersistenceManagerFactoryImpl.java:50)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
at org.jboss.mx.server.MBeanServerImpl.instantiate(MBeanServerImpl.java:909)