Hi Greg, thanks for exploring it further, I'll have a look myself at the bug and let you know.
Thanks, Tommaso 2013/2/13 Greg Holmberg <holmberg2...@comcast.net> > I tried it also with JDK 1.6.0_38 and got the same result. > > Further searching on the Clerezza mailing list revealed this issue, which > I think is the root cause of my problem: > > https://issues.apache.org/jira/browse/CLEREZZA-724 > > The reporter of this issue supplied a patch (to > ext.com.hp.hpl.jena.tdb/pom.xml), but it hasn't been applied yet. I will > get the Clerezza source code, apply the patch, build it, and see if it > changes anything for me. > > Greg > > ------------------------------ > *From: *"Greg Holmberg" <holmberg2...@comcast.net> > *To: *"Tommaso Teofili" <tommaso.teof...@gmail.com> > *Cc: *"uima user" <user@uima.apache.org> > *Sent: *Tuesday, February 12, 2013 1:21:56 AM > > *Subject: *Re: Clerezza and UIMA > > Hi Tom maso-- > > > Regarding the classloader, the purpose is to make the UIMAClassLoader the > default for the thread. The UIMAClassLoader has all the classes in the AE > Pear (which the boot classloader doesn't have--i.e. they weren't on the > command-line -cp). Without it being the default for the thread, some > dynamically loaded classes can't be found. For example, when using the > Clerezza libs, if I leave out the line that says > thread.setContextClassLoader(uimaClassLoader), then I get: > > org.apache.clerezza.rdf.core.serializedform.UnsupportedSerializationFormatException: > No serializer available for application/rdf+xml > at > org.apache.clerezza.rdf.core.serializedform.Serializer.serialize(Serializer.java:142) > > > I'm guessing that the serializers (implementations of an interface) ARE > loaded dynamically, and can be found in the > org.apache.clerezza.rdf.jena.serializer Jar, which is in the Pear file, but > not on the command line classpath. Somehow, when the above method, called > from my annotator's process() method somewhere below > AnalysisEngine.process(), tries to load those classes, it doesn't use the > UIMA classloader, but rather the thread's context classloader, which falls > back to the boot loader, which can't find them. > > On the other hand, if I do set the thread's context classloader to the > UIMA classloader, then I get the LinkageError for Xerces: > > Exception in thread "TAService Worker 0" java.lang.LinkageError: loader > constraint violation in interface itable initialization: when resolving > method > "org.apache.xerces.dom.ElementImpl.getSchemaTypeInfo()Lorg/w3c/dom/TypeInfo;" > the class loader (instance of > org/apache/uima/internal/util/UIMAClassLoader) of the current class, > org/apache/xerces/dom/ElementImpl, and the class loader (instance of > <bootloader>) for interface org/w3c/dom/Element have different Class > objects for the type m/TypeInfo; used in the signature > > So it seems I'm damn if I do, damned it I don't. How do I get out of this > catch-22? > > By the way, I'm using Oracle JDK 1.7.0_10, in case that matters. I'll also > try going back to 1.6.0 tomorrow to see if that makes any difference. > > > Thanks, > > Greg > > > > ----- Original Message ----- > From: "Tommaso Teofili" <tommaso.teof...@gmail.com> > To: "Greg Holmberg" <holmberg2...@comcast.net> > Cc: "uima user" <user@uima.apache.org> > Sent: Monday, February 11, 2013 12:35:56 AM > Subject: Re: Clerezza and UIMA > > > H Greg, > > > the code you're referring to [1] is used essentially for OSGi deployments, > where each bundle (the package jars) have their own Classloader and > essentially that would create issues when trying to instantiate AEs whose > classes are in different bundles than the one which "contains" the UIMA > framework. > The way it works is just that each bundle which needs to use UIMA has to > declare its UIMA components into an OSGi activator extending the > UIMABundleActivator and thus implementing the #classRegistered method, see > an example: > > > @Override > protected void classRegistered() { > classLoaderRepository.registerComponent(SomeAnnotator.class); > } > > > In the code you've shown it seems you're redefining the Classloader > instance to be used by UIMAFramework and also forcing it into the current > thread, as far as I have seen this is often done in OSGi deployments but I > wonder if that's your scenario or not, and if not which container are you > trying to instantiate UIMA into so that we can better understand what's the > linkage problem coming from. > > > Regards, > Tommas > > > [1] : > http://svn.apache.org/repos/asf/incubator/clerezza/trunk/uima/uima.utils/ > > > > 2013/2/7 Greg Holmberg < holmberg2...@comcast.net > > > > > > Hi Tommaso-- > > > Sorry for the direct email, but you seem to be the expert on combining > UIMA and Clerezza. > > I'm trying to generate RDF from my UIMA AE. I started with the code in > RDFCASConsumer.java and modified it to change the directory and file to > which the RDF is written. > > I put this in my AE and deployed it in UIMA, running in my own container. > This container does this: > > AnalysisEngine engine = UIMAFramework.produceAnalysisEngine(...); > ClassLoader uimaClassLoader = > engine.getResourceManager().getExtensionClassLoader(); > Thread thread = Thread.currentThread(); > thread.setContextClassLoader(uimaClassLoader); > engine.process(cas); > > When I run I get: > > Exception in thread "TAService Worker 0" java.lang.LinkageError: loader > constraint violation in interface itable initialization: when resolving > method > "org.apache.xerces.dom.ElementImpl.getSchemaTypeInfo()Lorg/w3c/dom/TypeInfo;" > the class loader (instance of > org/apache/uima/internal/util/UIMAClassLoader) of the current class, > org/apache/xerces/dom/ElementImpl, and the class loader (instance of > <bootloader>) for interface org/w3c/dom/Element have different Class > objects for the type m/TypeInfo; used in the signature > > > I see several issues in Clerezza about UIMA and classloaders, which you > have resolved. There's even a method that gets the classloader to be used > for XML parsing. > > So it seems like you've probably solved this problem related to Xerces and > classloaders. However, I can't find any documentation about how to use your > fix. > > Can you tell me what I need to do when creating my analysis engine and > setting the classloader in order to avoid this LinkageError? > > Thanks, > > > Greg Holmberg > > > > > > >
