Warnings for javassist when deploying a native Hibernate application in EAP 6

Environment

• Red Hat JBoss Enterprise Application Platform (EAP) 6
• Hibernate 4 (non-JPA/native Hibernate applications only)

Issue

• HHH000305: Could not create proxy factory ... HHH000142: Javassist Enhancement failed when deploying a native (non-JPA) Hibernate application

... WARN  [org.hibernate.tuple.entity.PojoEntityTuplizer] ... HHH000305: Could not create proxy factory for:org.test.MyEntity: org.hibernate.HibernateException: HHH000142: Javassist Enhancement failed: org.test.MyEntity
        at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.getProxyFactory(JavassistLazyInitializer.java:167)
        at org.hibernate.proxy.pojo.javassist.JavassistProxyFactory.postInstantiate(JavassistProxyFactory.java:66)
        at org.hibernate.tuple.entity.PojoEntityTuplizer.buildProxyFactory(PojoEntityTuplizer.java:229)
        ...
        at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:506)
        at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:146)
        ...
        at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:389)
        at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1799)
...
Caused by: java.lang.RuntimeException: by java.lang.NoClassDefFoundError: javassist/util/proxy/ProxyObject
        at javassist.util.proxy.ProxyFactory.createClass3(ProxyFactory.java:515)
        ...
        at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.getProxyFactory(JavassistLazyInitializer.java:163)
        ...
Caused by: javassist.CannotCompileException: by java.lang.NoClassDefFoundError: javassist/util/proxy/ProxyObject
        at javassist.util.proxy.FactoryHelper.toClass(FactoryHelper.java:170)
        at javassist.util.proxy.ProxyFactory.createClass3(ProxyFactory.java:507)
        ...
Caused by: java.lang.NoClassDefFoundError: javassist/util/proxy/ProxyObject
        at java.lang.ClassLoader.defineClass1(Native Method)
        ...
        at javassist.util.proxy.FactoryHelper.toClass2(FactoryHelper.java:182)
        at javassist.util.proxy.FactoryHelper.toClass(FactoryHelper.java:164)
        ... 62 more
Caused by: java.lang.ClassNotFoundException: javassist.util.proxy.ProxyObject ...
        at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:213)
        ...

• JBAS015867: Deployment ... is using a private module ("org.javassist:main") if an explicit module dependency is added to jboss-deployment-structure.xml

... WARN  [org.jboss.as.dependency.private] ... JBAS015867: Deployment ... is using a private module ("org.javassist:main") which may be changed or removed in future versions without notice.

Resolution

• The NoClassDefFoundError may be resolved by an explicit application dependency on org.javassist in jboss-deployment-structure.xml

<jboss-deployment-structure ...>
        <deployment>
                <dependencies>
                        ...
                        <module name="org.hibernate"/>
                        <module name="org.javassist"/>
                </dependencies>
        </deployment>
</jboss-deployment-structure>

• The JBAS015867 warning is non-fatal and there are presently no plans to remove support for javassist in EAP 6 so the warning may be ignored
• This is This content is not included.BZ-1288251 which is resolved by applying JBoss EAP 6.4 Cumulative Patch (CP) 6 or later
  • Resolution of the dependency as part of the fix for This content is not included.BZ-1288251 is meant only to support Hibernate's internal usage (e.g. in lazy fetch)
  • Applications should not use javassist directly/explicitly as this is not supported

Root Cause

• In order to leverage functionality such as lazy fetch, Hibernate requires bytecode instrumentation which is provided by javassist
  • This introduces a deployment time dependency manifested as the HHH000142 error for native Hibernate applications
• The JBAS015867 warning results from an explicit dependency introduced to resolve the NoClassDefFoundError
  • org.javassist is shipped as a private module because it is not part of the JavaEE standard and is not meant to be directly used by application code
  • This issue is unique to non-JPA/native Hibernate applications which require application configuration to resolve the the org.javassist dependency

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