Hi,I have a non-OSGi Java app that loads an OSGi bundle by embedding Felix. The
bundle exposes its functionality as an OSGi service. The app accesses the
service via a service tracker. The app uses the
org.osgi.framework.system.packages.extra option so that the service interface
and the classes that the interfaces refers to are all loaded by the same
classloader in both the app and the bundle.
The bundle uses Jersey 2.X and the app uses Jersey 1.17. When the app calls the
bundle via the service, the Jersey 2.X code throws the following exception:
Exception in thread "main" java.lang.LinkageError: ClassCastException:
attempting to castfile:/C:/XXX/bin/javax/ws/rs/ext/RuntimeDelegate.class to
bundle://59.1:1/javax/ws/rs/ext/RuntimeDelegate.classat
javax.ws.rs.ext.RuntimeDelegate.findDelegate(RuntimeDelegate.java:146) at
javax.ws.rs.ext.RuntimeDelegate.getInstance(RuntimeDelegate.java:120) at
javax.ws.rs.core.UriBuilder.newInstance(UriBuilder.java:95)...
Looking at the Jersey source code, it appears that RuntimeDelegate tries to
load a concrete subclass via javax.ws.rs.ext.FactoryFinder. FactoryFinder reads
the name of the subclass from file
META-INF/services/javax.ws.rs.ext.RuntimeDelegate, and it loads that file via
the calling threads's context class loader. Since the calling thread is an
application's thread, its class loader is the application's class loader, so
META-INF/services/javax.ws.rs.ext.RuntimeDelegate points to a Jersey 1.17 class.
I can kind-of workaround the problem by setting the application thread to an
"empty" class loader before calling the service - i.e.:
ClassLoader saveCL = Thread.currentThread().getContextClassLoader();
ClassLoader myCL = new URLClassLoader(new URL[0], saveCL.getParent());
try {
Thread.currentThread().setContextClassLoader(myCL);
call OSGi service
} finally {
Thrad.currentThread().setContextClassloader(saveCL);
}
However, I'm surprised I have to do that. Shouldn't the framework take care of
this - even if the service caller is the embedded application rather than
another OSGi bundle?
Notice: This issue may or may not be related to commons-logging and Axis
problems
Thank you in advance,Alessandro
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commons-logging and Axis problems
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