[FELIX-6109] NPE from null listener in DirectoryWatcher.findListener

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: fileinstall-3.6.4
• Fix Version/s: fileinstall-3.6.6
• Component/s: File Install
• Assignee: Guillaume Nodet
• Reporter: Stephen Marquard
• Created: 27/Apr/19 06:49
• Updated: 01/Apr/20 12:02
• Resolved: 01/Apr/20 12:02

Description

This error shows up intermittently in an OSGI application:

 

*ERROR* [org.osgi.service.cm.ManagedServiceFactory, id=13, bundle=6/file:/opt/ls/bundles/system/org.apache.felix.fileinstall-3.6.4.jar]: Unexpected problem updating configuration org.apache.felix.fileinstall.06a753e4-56fc-42fa-8a5b-c2b0b374581f

java.lang.NullPointerException

 at org.apache.felix.fileinstall.internal.DirectoryWatcher.findListener(DirectoryWatcher.java:533)

 at org.apache.felix.fileinstall.internal.DirectoryWatcher.doProcess(DirectoryWatcher.java:460)

 at org.apache.felix.fileinstall.internal.DirectoryWatcher.process(DirectoryWatcher.java:365)

 at org.apache.felix.fileinstall.internal.DirectoryWatcher.start(DirectoryWatcher.java:247)

 at org.apache.felix.fileinstall.internal.FileInstall.updated(FileInstall.java:254)

 at org.apache.felix.fileinstall.internal.FileInstall$ConfigAdminSupport$Tracker.updated(FileInstall.java:378)

 at org.apache.felix.cm.impl.helper.ManagedServiceFactoryTracker.updated(ManagedServiceFactoryTracker.java:159)

 at org.apache.felix.cm.impl.helper.ManagedServiceFactoryTracker.provideConfiguration(ManagedServiceFactoryTracker.java:93)

 at org.apache.felix.cm.impl.ConfigurationManager$UpdateConfiguration.run(ConfigurationManager.java:1400)

 at org.apache.felix.cm.impl.UpdateThread.run0(UpdateThread.java:138)

 at org.apache.felix.cm.impl.UpdateThread.run(UpdateThread.java:105)

 at java.lang.Thread.run(Thread.java:748)

 

 The NPE seems to imply that there is a null listener in the list of listeners here:

 

  ArtifactListener findListener(File artifact, List<ArtifactListener> listeners)
    {
        for (ArtifactListener listener : listeners) {
            if (listener.canHandle(artifact)) {
                return listener;
            }
        }
        return null;

 

I don't know how that situation arises (some type of race condition, given that it's unpredictable), but seems like it should be easy enough to check for and ignore.