OSGi bundle's Activator class not found

Question

I have an OSGi bundle, which has an activator class. I embedded Equinox in my webapp, and installed my bundle in it. The installation goes well, but when I try to start the bundle, the following error comes:

org.osgi.framework.BundleException: The activator com.rr.fr.base.barcode.activator.Activator for bundle fr-base-barcode is invalid
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.loadBundleActivator(AbstractBundle.java:171)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:679)
    at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:381)
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.start(AbstractBundle.java:299)
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.start(AbstractBundle.java:291)
    at com.rr.fr.base.osgi.BundleStarter.launch(BundleStarter.java:43)
    at com.rr.fr.base.osgi.OsgiInitServletContextListener.contextInitialized(OsgiInitServletContextListener.java:41)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4210)
    at org.apache.catalina.core.StandardContext.start(StandardContext.java:4709)
    at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1060)
    at org.apache.catalina.core.StandardHost.start(StandardHost.java:822)
    at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1060)
    at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)
    at org.apache.catalina.core.StandardService.start(StandardService.java:525)
    at org.apache.catalina.core.StandardServer.start(StandardServer.java:759)
    at org.apache.catalina.startup.Catalina.start(Catalina.java:595)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
Caused by: java.lang.ClassNotFoundException: com.rr.fr.base.barcode.activator.Activator
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:513)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:429)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:417)
    at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at org.eclipse.osgi.internal.loader.BundleLoader.loadClass(BundleLoader.java:345)
    at org.eclipse.osgi.framework.internal.core.BundleHost.loadClass(BundleHost.java:229)
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.loadBundleActivator(AbstractBundle.java:164)
    ... 21 more

I can see that my activator class was not found. I searched for a solution and find some interesting thing here in SO, but none of them helped me.

Here is my manifest:

Manifest-Version: 1.0
Bnd-LastModified: 1431100911346
Build-Jdk: 1.6.0_45
Bundle-Activator: com.rr.fr.base.barcode.activator.Activator
Bundle-ManifestVersion: 2
Bundle-SymbolicName: fr-base-barcode;singleton:=true
Bundle-Version: 0.1.2.SNAPSHOT
Created-By: Apache Maven Bundle Plugin
Import-Package: com.rr.fr.base.barcode.qrcode.interfaces,com.rr.fr.base.
 exception,com.rr.fr.base.messages,com.rr.fr.base.system,com.rr.fr.base.
 types,com.rr.fr.interfaces,com.rr.fr.interfaces.eb.rms,com.rr.fr.ui.htt
 p,hu.posta.rsaqrgen,javax.servlet,javax.servlet.http,org.apache.avalon.
 framework.configuration,org.apache.commons.logging,or
 g.krysalis.barcode4j,org.krysalis.barcode4j.output,org.krysalis.barcode
 4j.output.bitmap,org.krysalis.barcode4j.output.eps,org.osgi.framework,org.osgi.service.http,org.osgi.util.
 tracker

I can include my Activator, but I don't think it would help since it isn't even found so I don't think its source has anything to do with the error.

My bundle's library structure inside the JAR is the following:

META-INF
    /MANIFEST.MF
target
    /classes
        /com
            /rr
                /fr
                    /base
                        /barcode
                            ...
fr-base-barcode.jar
plugin.xml

I create my bundle with Eclipse PDE: Export.../Deployable Plug-ins and fragments

My build.properties includes the META-INF and target libraries, a JAR and plugin.xml as it can be seen in the bundle structure.

Any help would be appreciated.

That "target/classes" folder looks wrong. I assume that's being added by the Maven plugin. Perhaps try manually rebuilding the JAR without that to see if it's the problem? — Brett Kail
The nested fr-base-barcode.jar isn't going to work without a Bundle-ClassPath either. I guess you could try Bundle-Classpath: target/classes fr-base-barcode.jar, but I would still try to figure out how to get rid of that target/classes folder since it's rather atypical. — Brett Kail
Thanks for your answer. Could you please specify what is actually wrong with the target/classes folder? Of course under the /barcode folder there are more folders with the class files inside, for example the activator/Activator.class So the activator class is 'com.rr.fr.base.barcode.activator.Activator.class' Shouldn't the class files be in such a structure? — Tamas G.
And that way it works! Thank you very much! If you write an answer, I can accept it. — Tamas G.

ebullient ebullient · Accepted Answer · 2015-05-08T17:27:15

I'm going to restate bkail's suggestion as the answer. When your packages are included in the "target/classes" folder, they are essentially in that package: target.classes.com.rr.fr.base.barcode.*

The root of your package structure (com) should be a peer of META-INF and/or OSGI-INF, etc.

OSGi bundle's Activator class not found

2 Answers