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java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory in OSGi

I'm trying to get the library BioJava to work inside an OSGi context.
To get the JAR into the OSGi context, I'm using the Maven plugin p2-maven-plugin, which generates a file Manifest.MF, and the part relevant to the exception I'm facing is:
Bundle-SymbolicName: org.biojava.core
Bundle-Version: 5.3.0
Import-Package: [snip],
org.slf4j;resolution:=optional,
[snap]
Which looks okay to me. However when I access a class that uses slf4j I get the titular exception:
java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
at org.biojava.nbio.core.sequence.template.AbstractCompoundSet.<clinit>(AbstractCompoundSet.java:40)
at org.biojava.nbio.core.sequence.io.ABITrace.getSequence(ABITrace.java:179)
Caused by: java.lang.ClassNotFoundException: org.slf4j.LoggerFactory cannot be found by org.biojava.core_5.3.0
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:511)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:422)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:414)
Now it's easy to find this exception everywhere, because a lot of people have tried (and failed) to install slf4j. I checked sites like the documentation or the SO question ClassNotFoundException: org.slf4j.LoggerFactory and hence tried to add the following bundles:
slf4j-simple
slf4j-log4j12 (plus the log4j dependencies)
pax-logging-log4j2
However neither worked. Maybe the OSGi container is having problems, but slf4j JARs have the bundle information with the export packages out of the box, so I'm assuming these work. And the BioJava JAR has an import package, so I have no idea why it wouldn't be able to find the class.
Oh, I checked, the LoggerFactory is present in slf4j-api, so it's not that, either.
I also tried different start levels and autostart for the implementations. And I rebundled the JAR without the optional dependency, but I keep having problems because now the MD5 hash is broken.
Has anybody managed to get slf4j to work in OSGi? Or failing that, is there any way to replace that stupid dependency with some kind of Java proxy so I will not need the broken dependency anymore?

resolution:=optional means that when the bundle resolves, it will either get access to the package or not. The framework is permitted to resolve the bundle without access to the package. If the bundle needs access to the package, why make resolution of the package optional?

starting slf4j bundle doesn't start on felix

I have felix-framework-5.0.1 and I'm trying to start slf4j-api-1.6.0.jar bundle into felix isgi container.
in felix console I'm typing install file:bundle/slf4j-api-1.6.0.jar
I'm getting a message Bundle ID: 42
then I'm trying to start the bundle start 42
I'm getting the message
org.osgi.framework.BundleException: Unable to resolve slf4j.api [42](R 42.0): missing requirement [slf4j.api [42](R 42.0)] osgi.wiring.package; (&(osgi.wiring.p
ackage=org.slf4j.impl)(version>=1.5.5)) Unresolved requirements: [[slf4j.api [42](R 42.0)] osgi.wiring.package; (&(osgi.wiring.package=org.slf4j.impl)(version>=
1.5.5))]
g!
Can any body help me? how can I start slf4j bundle into felix?

slf4j-api needs org.slf4j.impl package. This package is included into every slf4j implementations like slf4j-simple, slf4j-logback, etc.
The implementation bundles need org.slf4j package that comes from the API artifact. There is a cross-reference. This can work only due to the reason that implementations are fragment bundles of the API. When the implementation is installed together with the API, they will have a common classloader and they will be resolved together. Both of their requirements will be satisfied.
In short: You must choose one of the implementations and install that as well. E.g.: slf4j-simple.
You should use the same version of API and implementation to satisfy their "cross requirement".

Your library contains the following 3 packages (link):
org.slf4j
org.slf4j.helpers
org.slf4j.spi
but you have to have an additional library that will contain org.slf4j.impl package.
Also, from manifest file you can see what packages are exported (Export-Package) (they are visible by other bundles) and what packages are imported (Import-Package) (they have to be accessible for the given bundle). Sometimes the given package have to be from bundle with the correct version.
If you cannot find correct bundle maybe this page will help you.

Adding akka dependencies to osgi container

I use osgi container (virgo) [i'm not very good in that].
I added a dependency to my pom.xml
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-osgi_2.10</artifactId>
<version>2.2-M3</version>
</dependency>
I put akka-osgi_2.10-2.2-M3.jar to my lib/deploy folder to OSGI server (to myserver/repository/usr).
I added dummy actor to my code base:
import akka.actor.UntypedActor;
public class ManagerActor extends UntypedActor {
#Override
public void onReceive(Object o) throws Exception {
// ...
}
}
I build and start my application.
And as result I have the following exceptions in my log (it complains to version="0.0.0"):
.. failed. org.eclipse.virgo.kernel.osgi.framework.UnableToSatisfyBundleDependenciesException: Unable to satisfy dependencies of bundle 'com.
com.mycompnay.mything-security' at version '1.0.1.BUILD-SNAPSHOT': Cannot resolve: com.mycompany.mything-security
Resolver report:
An Import-Package could not be resolved. Resolver error data <Import-Package: akka.actor; version="0.0.0">. Caused by missing constrai
nt in bundle <com.mycompany.mything-security_1.0.1.BUILD-SNAPSHOT>
constraint: <Import-Package: akka.actor; version="0.0.0">
I go to my template.mf file, which is used to generate final MANIFEST.MF file. To specify the range of versions for AKKA lib I use. Putting there:
Import-Template:
akka.actor.*;version="[2.2.0.M3, 2.3)"
Import-Package:
akka.actor;version="[2.2.0.M3, 2.3)"
Then rebuild and start app.
But in console it complains to akka versions (complains to version="[2.2.0.M3,2.3.0)" now):
An Import-Package could not be resolved. Resolver error data <Import-Package: akka.actor; version="[2.2.0.M3,2.3.0)">. Caused by missi
ng constraint in bundle <com.mycompany.mything-security_1.0.1.BUILD-SNAPSHOT>
constraint: <Import-Package: akka.actor; version="[2.2.0.M3,2.3.0)">
Q: what's wrong?
Also I tried to add this line: to Import-Bundle:
Import-Bundle:
...
com.typesafe.akka.osgi;version="[2.2.0.M3, 2.3)"
Then I have it in the log (now it complains to com.typesafe.akka.osgi version):
.. failed. org.eclipse.virgo.kernel.deployer.core.DeploymentException: Unable to satisfy dependencies of bundle 'com.mycompany.mything-security
' at version '1.0.1.BUILD-SNAPSHOT': Import-Bundle with symbolic name 'com.typesafe.akka.osgi' in version range '[2.2.0.M3, oo)' could not be
satisfied

The reason was:
I need to put akka-actor_2.10-2.2-M3.jar (along with akka-osgi_2.10-2.2-M3.jar) to my osgi (virgo) deploy folder.
So, we should NOT do it manually but with help of maven (in order not to miss some jar that comes along with expecting one).

Unresolved constraint when trying to export a simple interface

I'm trying to take the first steps in familiarizing myself to OSGI framework.
However, I'm not even able to start the bundle which only exports one package, nothing more.
The error the framework shows sounds ridiculous to me as I read it as 'In order to start your bundle I need to resolve openjsip.service.locationservice package.
But this package comes from my bundle !
Anyway, I think I'm wrong, but I can't grasp the problem, could somebody help me ?
ERROR: Bundle openjsip.locationservice [6] Error starting file:////tmp/locationservice-1.0.0-SNAPSHOT.jar (org.osgi.framework.BundleException: Unresolved constraint in bundle openjsip.locationservice [6]: Unable to resolve 6.0: missing requirement [6.0] osgi.wiring.package; (&(osgi.wiring.package=openjsip.service.locationservice)(version>=1.0.0)))
org.osgi.framework.BundleException: Unresolved constraint in bundle openjsip.locationservice [6]: Unable to resolve 6.0: missing requirement [6.0] osgi.wiring.package; (&(osgi.wiring.package=openjsip.service.locationservice)(version>=1.0.0))
at org.apache.felix.framework.Felix.resolveBundleRevision(Felix.java:3826)
at org.apache.felix.framework.Felix.startBundle(Felix.java:1868)
at org.apache.felix.framework.Felix.setActiveStartLevel(Felix.java:1191)
at org.apache.felix.framework.FrameworkStartLevelImpl.run(FrameworkStartLevelImpl.java:295)
at java.lang.Thread.run(Thread.java:722)
Here is my MANIFEST.MF:
Manifest-Version: 1.0
Bnd-LastModified: 1348338100498
Build-Jdk: 1.7.0_05
Built-By: devel
Bundle-ManifestVersion: 2
Bundle-Name: locationservice
Bundle-SymbolicName: openjsip.locationservice
Bundle-Version: 1.0.0.SNAPSHOT
Created-By: Apache Maven Bundle Plugin
Export-Package: openjsip.service.locationservice;uses:="javax.sip.header
,javax.sip";version="1.0.0.SNAPSHOT"
Import-Package: javax.sip;version="[1.2,2)",javax.sip.header;version="[1
.2,2)"
Tool: Bnd-1.50.0

The error message doesn't seem to match the MANIFEST.MF you have posted. Is it possible that you have rebuilt it in-between?
The error message says that your bundle imports the package openjsip.service.locationservice, and that import could not be resolved. However according to the manifest you only import javax.sip and javax.sip.header. Therefore this error message could not have come from the bundle manifest posted.

Thanks everybody for help, the issue was really with IDEA configuration, where it creates MANIFEST.MF by itself using facet configuration (which I left empty relying on apache maven plugin). For some reason it ignores this plugin or can't work in pair with it yet.
The resolution was to tell it 'Use predefined MANIFEST.MF from target/classes/META-INF'.
Thanks again.

Force OSGi package to be imported by maven-bundle-plugin / BND

I try to package an OSGI bundle using the maven-bundle-plugin (which uses BND).
To run properly the bundle must import a package which is not in the classpath during development (because object references will be passed to the bundle methods as "Class" references).
I do not manage to configure the "Import-Package" declaration in the pom.xml or *.bnd file so that the packe will be included in the OSGI Import-Package part of the MANIFEST. I though
Import-Package: de.foo.bar,*
should do the job, but as de.foo.bar is not in the classpath (or better not declared as an import in the code) it will not be taken to the MANIFEST.
Has anybody an idea how to force the package to be available in the OSGi Import-Package MANIFEST declaration.
Thanks and regards
Klaus

I finally found a solution
Import-Package: de.foo.bar;resolution:=optional,*
will put "de.foo.bar" in the "Import-Package" declaration of the bundle MANIFEST.MF even if the package is not imported by the bundle code.