Why receiving java.lang.ClassNotFoundException: xxx.yyy.zzz.TestClass not found by org.hibernate.core ?

Issue

• We are migrating to Fuse 6.2 and hence from Hibernate 3 to 4. We changed the Spring configuration to use hibernate4 SessionFactory and TransactionManager. However we are getting the following error:

JBossFuse:karaf@root> Exception in thread "SpringOsgiExtenderThread-2" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in URL [bundle://286.0:0/META-INF/spring/datasource.xml]: Invocation of init method failed; nested exception is org.hibernate.AssertionFailure: PersistentClass name cannot be converted into a Class
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1514)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:521)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:293)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:290)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:191)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:618)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:934)
    at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext.access$1600(AbstractDelegatedExecutionApplicationContext.java:69)
    at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext$4.run(AbstractDelegatedExecutionApplicationContext.java:355)
    at org.springframework.osgi.util.internal.PrivilegedUtils.executeWithCustomTCCL(PrivilegedUtils.java:85)
    at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext.completeRefresh(AbstractDelegatedExecutionApplicationContext.java:320)
    at org.springframework.osgi.extender.internal.dependencies.startup.DependencyWaiterApplicationContextExecutor$CompleteRefreshTask.run(DependencyWaiterApplicationContextExecutor.java:132)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.hibernate.AssertionFailure: PersistentClass name cannot be converted into a Class
    at org.hibernate.cfg.BinderHelper.getPropertyOverriddenByMapperOrMapsId(BinderHelper.java:816)
    at org.hibernate.cfg.AnnotationBinder.processElementAnnotations(AnnotationBinder.java:2097)
    at org.hibernate.cfg.AnnotationBinder.processIdPropertiesIfNotAlready(AnnotationBinder.java:895)
    at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:728)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processAnnotatedClassesQueue(Configuration.java:3625)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processMetadata(Configuration.java:3579)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1381)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1786)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1870)
    at org.springframework.orm.hibernate4.LocalSessionFactoryBuilder.buildSessionFactory(LocalSessionFactoryBuilder.java:252)
    at org.springframework.orm.hibernate4.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:377)
    at org.springframework.orm.hibernate4.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:362)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1573)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1511)
    ... 14 more
Caused by: java.lang.ClassNotFoundException: xxx.yyy.zzz.TestClass not found by org.hibernate.core [281]
    at org.apache.felix.framework.BundleWiringImpl.findClassOrResourceByDelegation(BundleWiringImpl.java:1556)
    at org.apache.felix.framework.BundleWiringImpl.access$400(BundleWiringImpl.java:77)
    at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.loadClass(BundleWiringImpl.java:1993)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:344)
    at org.hibernate.annotations.common.util.ReflectHelper.classForName(ReflectHelper.java:60)
    at org.hibernate.annotations.common.reflection.java.JavaReflectionManager.classForName(JavaReflectionManager.java:138)
    at org.hibernate.cfg.BinderHelper.getPropertyOverriddenByMapperOrMapsId(BinderHelper.java:812)
    ... 27 more

• After enabling dynamic-import on hibernate-core bundle, exception above got resolved but another exception received. Below is the exception.

Caused by: java.lang.NoClassDefFoundError: org/hibernate/proxy/HibernateProxy
    at java.lang.ClassLoader.defineClass1(Native Method)[:1.7.0_67]
    at java.lang.ClassLoader.defineClass(ClassLoader.java:800)[:1.7.0_67]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)[:1.7.0_67]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)[:1.7.0_67]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)[:1.7.0_67]
    at java.lang.reflect.Method.invoke(Method.java:606)[:1.7.0_67]
    at javassist.util.proxy.FactoryHelper.toClass2(FactoryHelper.java:182)
    at javassist.util.proxy.FactoryHelper.toClass(FactoryHelper.java:164)
    ... 56 more
Caused by: java.lang.ClassNotFoundException: org.hibernate.proxy.HibernateProxy not found by Test_Custom_Module [304]