I have built an OSGi bundle that uses Apache CXF (I embedded the dependency in
my bundle). I encountered a very strange error:
java.lang.LinkageError: loader constraint violation: when resolving overridden
method
"org.apache.cxf.jaxb.attachment.JAXBAttachmentMarshaller.addMtomAttachment(Ljavax/activation/DataHandler;Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;"
the class loader (instance of
org/apache/felix/framework/BundleWiringImpl$BundleClassLoaderJava5) of the
current class, org/apache/cxf/jaxb/attachment/JAXBAttachmentMarshaller, and its
superclass loader (instance of <bootloader>), have different Class objects for
the type
org.apache.cxf.jaxb.attachment.JAXBAttachmentMarshaller.addMtomAttachment(Ljavax/activation/DataHandler;Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;
used in the signature
at
org.apache.cxf.jaxb.JAXBDataBase.getAttachmentMarshaller(JAXBDataBase.java:82)
After puzzling through it for a while I determined that the class
javax.activation.DataHandler was the problem; it's being loaded from the Sling
bundle by one classloader, and from the JRE by the other. The javax.activation
package is now included as part of the JRE so I am not sure why the Sling
bundle is included. I figured I would just exclude it:
<plugin>
<groupId>org.apache.sling</groupId>
<artifactId>maven-launchpad-plugin</artifactId>
<version>2.3.2</version>
...
<bundleExclusions>
<bundle>
<groupId>org.apache.sling</groupId>
<artifactId>org.apache.sling.javax.activation</artifactId>
<version>0.1.0</version>
</bundle>
</bundleExclusions>
</configuration>
</plugin>
This knocked out the bundle correctly but my own bundle could no longer resolve
javax.activation. I find this odd as it is explicitly called out in the default
Felix configuration at
http://svn.apache.org/viewvc/felix/trunk/framework/src/main/resources/default.properties?view=markup
as a system package that should be exported. So, I added it to my own
sling_install.properties:
org.osgi.framework.system.packages.extra=javax.activation
This solved the problem and I was able to see that my bundle imported the
package from the JRE. My code runs now but I wanted to bring this situation to
someone's attention.
