Question

My hibernate setup throws some exceptions but still works. The exceptions are thrown for every entity class defined in mapping xml. My project sets up on OSGI using equinox. The class which could not be found is definitely in classpath.

Hibernate Configuration

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="connection.driver_class">com.package.Driver</property>
        <property name="hibernate.connection.url">url</property>
        <property name="hibernate.connection.username">username</property>
        <property name="hibernate.connection.password">password</property>
        <property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>
        <property name="dialect">org.hibernate.dialect.H2Dialect</property>
        <property name="current_session_context_class">thread</property>
        <property name="hibernate.cache.use_second_level_cache">false</property>
        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
        <property name="show_sql">false</property>
        <!-- C3P0 Connection Pool -->
        <property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
        <property name="hibernate.c3p0.min_size">5</property>
        <property name="hibernate.c3p0.max_size">20</property>
        <property name="hibernate.c3p0.timeout">300</property>
        <property name="hibernate.c3p0.max_statements">50</property>
        <property name="hibernate.c3p0.idle_test_period">3000</property>
    </session-factory>
</hibernate-configuration>

Exception

Javassist Enhancement failed: at.mkw.inlocs.common.Mapping
java.lang.RuntimeException: by java.lang.NoClassDefFoundError: org/hibernate/proxy/HibernateProxy
    at javassist.util.proxy.ProxyFactory.createClass3(ProxyFactory.java:344)
    at javassist.util.proxy.ProxyFactory.createClass2(ProxyFactory.java:314)
    at javassist.util.proxy.ProxyFactory.createClass(ProxyFactory.java:273)
    at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.getProxyFactory(JavassistLazyInitializer.java:163)
    at org.hibernate.proxy.pojo.javassist.JavassistProxyFactory.postInstantiate(JavassistProxyFactory.java:66)
    at org.hibernate.tuple.entity.PojoEntityTuplizer.buildProxyFactory(PojoEntityTuplizer.java:187)
    at org.hibernate.tuple.entity.AbstractEntityTuplizer.<init>(AbstractEntityTuplizer.java:170)
    at org.hibernate.tuple.entity.PojoEntityTuplizer.<init>(PojoEntityTuplizer.java:77)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:107)
    at org.hibernate.tuple.entity.EntityTuplizerFactory.constructDefaultTuplizer(EntityTuplizerFactory.java:135)
    at org.hibernate.tuple.entity.EntityEntityModeToTuplizerMapping.<init>(EntityEntityModeToTuplizerMapping.java:80)
    at org.hibernate.tuple.entity.EntityMetamodel.<init>(EntityMetamodel.java:323)
    at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:475)
    at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:133)
    at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:84)
    at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:295)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1385)
    at at.mkw.inlocs.syncservice.client.LocalDatabase.configureHibernate(LocalDatabase.java:80)
    at at.mkw.inlocs.syncservice.client.LocalDatabase.login(LocalDatabase.java:153)
    at at.mkw.inlocs.swingclient.StartupHandler.createMainframe(StartupHandler.java:123)
    at at.mkw.inlocs.swingclient.Activator.runSwing(Activator.java:142)
    at at.mkw.inlocs.swingclient.Activator.access$6(Activator.java:71)
    at at.mkw.inlocs.swingclient.Activator$7.run(Activator.java:236)
    at java.awt.event.InvocationEvent.dispatch(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$000(Unknown Source)
    at java.awt.EventQueue$1.run(Unknown Source)
    at java.awt.EventQueue$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: javassist.CannotCompileException: by java.lang.NoClassDefFoundError: org/hibernate/proxy/HibernateProxy
    at javassist.util.proxy.FactoryHelper.toClass(FactoryHelper.java:169)
    at javassist.util.proxy.ProxyFactory.createClass3(ProxyFactory.java:339)
    ... 40 more
Caused by: java.lang.NoClassDefFoundError: org/hibernate/proxy/HibernateProxy
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(Unknown Source)
    at java.lang.ClassLoader.defineClass(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at javassist.util.proxy.FactoryHelper.toClass2(FactoryHelper.java:181)
    at javassist.util.proxy.FactoryHelper.toClass(FactoryHelper.java:163)
    ... 41 more
Caused by: java.lang.ClassNotFoundException: org.hibernate.proxy.HibernateProxy
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:494)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:410)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:398)
    at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:105)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 50 more

Answer 1

This is a common issue with using Hibernate in an OSGi environment. The issue is each bundle has its own class loader and when Hibernate Class.forname() is used in hibernate it throws an exception because your mapped class is not on the class path of hibernate class loader. the way around this in equinox is to use what is called buddy class loading. Where in the manfiest of the bundle that contains your hibernate jars you add this:

Eclipse-BuddyPolicy: registered

Then in the bundle or bundles with mapped classes you add this assuming the name of your hibernate bundle org.hibernate

Eclipse-RegisterBuddy: org.hibernate

Also for it to work you need to add the hibernate bundle as a dependency not through imported packages so make sure this is added in your bundle with mapped classes as well.

Require-Bundle: org.hibernate

For more information google hibernate buddy