BundleException with no bundle constraint specified

Symptoms -- What Goes Wrong

A plugin fails to load at runtime, and the log contains an OsgiContainerException with a BundleException as its root cause. For example:

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WARNING: Unable to enable plugin 'com.atlassian.myplugin.my-plugin'
com.atlassian.plugin.osgi.container.OsgiContainerException: Cannot start plugin: com.atlassian.myplugin.my-plugin
       at com.atlassian.plugin.osgi.factory.OsgiPlugin.enableInternal(OsgiPlugin.java:385)
       at com.atlassian.plugin.impl.AbstractPlugin.enable(AbstractPlugin.java:212)
       ...
Caused by: org.osgi.framework.BundleException: Unable to resolve due to constraint violation.
       at org.apache.felix.framework.Felix._resolveBundle(Felix.java:1732)
       at org.apache.felix.framework.Felix._startBundle(Felix.java:1588)
       at org.apache.felix.framework.Felix.startBundle(Felix.java:1541)
       at org.apache.felix.framework.BundleImpl.start(BundleImpl.java:371)

Cause

If your plugin is failing to enable with the message "Unable to resolve due to constraint violation." but doesn't specify a particular package or what the constraint violation is, it's possible that the exporter of a package that you are importing is imposing a uses constraint directive that your plugin is not satisfying. You may need to add a <Package-Import> to your own plugin to satisfy this directive.

Resolution

At the moment, determining which bundle imposes a uses constraint is primarily guesswork. You will need to look through the META-INF/manifest.mf files of bundles from which you are importing packages looking for uses directives in the Export-Package: section.

For example:

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Manifest-Version: 1.0
Export-Package: com.pyxis.greenhopper;uses:="javax.xml.bind.annotation";version:="4.3.1"
Import-Package: javax.xml.bind.annotation;version="2.1.0"

The uses:="javax.xml.bind.annotation" implies that plugins importing both com.pyxis.greenhopper and javax.xml.bind.annotation must import version "2.1.0" of javax.xml.bind.annotation. This can be achieved by adding the relevant <Package-Import> to your pom.xml:

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<build>
<plugins>
  <plugin>
    <groupId>org.apache.felix</groupId>
    <artifactId>maven-bundle-plugin</artifactId>
    <extensions>true</extensions>
    <configuration>
      <instructions>        
        <Import-Package>          
          javax.xml.bind*;version="2.1.0", <!-- note the specified version String -->
          *
        </Import-Package>        
        <Spring-Context>*;timeout:=60</Spring-Context>
      </instructions>
    </configuration>
  </plugin>
</plugins>
</build>