Details
Major Description
Some of the Seam modules (like Seam Persistence) contain optional Maven dependencies. The persistence module for example declares Hibernate as an provided dependency. The Seam Persistence module contains only one single class that requires Hibernate which is an SPI implementation to support specific Hibernate features. This class is only loaded/used if Hibernate is detected. Furthermore it's important to know that this bean is not meant to be a bean manged by the CDI runtime. Therefore it is annotated with @Veto (Seam Solder API) to get vetoed during CDI startup.
All this works very fine with Weld 1.1.x. Unfortunately OWB fails to deploy the Seam Persistence JAR with the following exception:
SCHWERWIEGEND: Exception sending context initialized event to listener instance of class org.apache.webbeans.servlet.WebBeansConfigurationListener
java.lang.NoClassDefFoundError: org/hibernate/TransientObjectException
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at org.apache.webbeans.util.ClassUtil.getClassFromName(ClassUtil.java:115)
at org.apache.webbeans.corespi.scanner.AbstractMetaDataDiscovery.getBeanClasses(AbstractMetaDataDiscovery.java:209)
at org.apache.webbeans.config.BeansDeployer.checkStereoTypes(BeansDeployer.java:732)
at org.apache.webbeans.config.BeansDeployer.deploy(BeansDeployer.java:160)
at org.apache.webbeans.lifecycle.AbstractLifeCycle.startApplication(AbstractLifeCycle.java:127)
at org.apache.webbeans.web.lifecycle.WebContainerLifecycle.startApplication(WebContainerLifecycle.java:88)
at org.apache.webbeans.servlet.WebBeansConfigurationListener.contextInitialized(WebBeansConfigurationListener.java:85)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4723)
at org.apache.catalina.core.StandardContext$1.call(StandardContext.java:5226)
at org.apache.catalina.core.StandardContext$1.call(StandardContext.java:5221)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:679)
Caused by: java.lang.ClassNotFoundException: org.hibernate.TransientObjectException
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1678)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1523)
... 17 more
For me it looks like the class scanner tries to build a set of Class objects from all classes in the bean archive. But this fails as soon as the class compiled against the Hibernate API is picked up as Hibernate is not on the classpath.
If I remember correctly Weld 1.0.x had similar issues. Somehow this was resolved in Weld 1.1.x but I don't know anything about the details.
I think OWB could handle NoClassDefFoundErrors a bit nicer. Currently OWB doesn't support bean archives that have optional dependencies at all. So an archive that contains just one class for which not all dependencies (classes) are accessible from the ClassLoader completely fails to deploy using OWB. Even if this class isn't used at all (neither within CDI nor manually instantiated in the application code).
I think it would be easy to fix this. ClassUtil.getClassFromName() or AbstractMetaDataDiscovery.getBeanClasses() could catch NoClassDefFoundError and handles them in some way. I think it would make sense to simply ignore such errors during the bean archive scanning process on continue with the next class.