NullpointerException in HttpServiceStarted when registering Servlet in Declarative Service with WebContainer as referenced Service [PAXWEB-313]

Andreas Klotz created PAXWEB-313

We are using a Declarative Service which depends on org.ops4j.pax.web.service.WebContainer.
In this services activate-method we register a servlet at the bound WebContainer.
As far as I understand the code of Pax Web, it seems that the WebContainer-Service is registerede
in the start-method of org.ops4j.pax.web.service.internal.Activator. This happens implicit by
opening the Service Tracker:
<pre>
ServiceTracker st = new ServiceTracker(bundleContext,
ServerControllerFactory.class.getName(),
new DynamicsServiceTrackerCustomizer());
st.open();
</pre>
So this Registration of the WebContainer-Service triggers our servlet registration while
ServletEventDispatcher is not initialized. That causes the NullPointerException.

Could'nt the Registration of the WebContainer-Service (opening the ServiceTracker) be
done after initializing the ServletEventDispatcher?

java.lang.NullPointerException
at org.ops4j.pax.web.service.internal.HttpServiceStarted.registerResources(HttpServiceStarted.java:181)
at org.ops4j.pax.web.service.internal.HttpServiceProxy.registerResources(HttpServiceProxy.java:66)
at de.ndesign.npat.frontend.ZKFrontend.activate(ZKFrontend.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.eclipse.equinox.internal.ds.model.ServiceComponent.activate(ServiceComponent.java:210)
at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.activate(ServiceComponentProp.java:139)
at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.build(ServiceComponentProp.java:339)
at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponent(InstanceProcess.java:588)
at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponents(InstanceProcess.java:196)
at org.eclipse.equinox.internal.ds.Resolver.getEligible(Resolver.java:328)
at org.eclipse.equinox.internal.ds.SCRManager.serviceChanged(SCRManager.java:221)
at org.eclipse.osgi.internal.serviceregistry.FilteredServiceListener.serviceChanged(FilteredServiceListener.java:104)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.dispatchEvent(BundleContextImpl.java:933)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:227)
at org.eclipse.osgi.framework.eventmgr.ListenerQueue.dispatchEventSynchronous(ListenerQueue.java:149)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.publishServiceEventPrivileged(ServiceRegistry.java:756)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.publishServiceEvent(ServiceRegistry.java:711)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistrationImpl.register(ServiceRegistrationImpl.java:130)
at org.eclipse.osgi.internal.serviceregistry.ServiceRegistry.registerService(ServiceRegistry.java:206)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.registerService(BundleContextImpl.java:507)
at org.ops4j.pax.web.service.internal.Activator.createHttpServiceFactory(Activator.java:155)
at org.ops4j.pax.web.service.internal.Activator.access$1200(Activator.java:83)
at org.ops4j.pax.web.service.internal.Activator$DynamicsServiceTrackerCustomizer.addingService(Activator.java:383)
at org.osgi.util.tracker.ServiceTracker$Tracked.customizerAdding(ServiceTracker.java:896)
at org.osgi.util.tracker.AbstractTracked.trackAdding(AbstractTracked.java:261)
at org.osgi.util.tracker.AbstractTracked.trackInitial(AbstractTracked.java:184)
at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:339)
at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:273)
at org.ops4j.pax.web.service.internal.Activator.start(Activator.java:116)
at org.ops4j.pax.web.service.jetty.internal.CompositeActivator.start(CompositeActivator.java:46)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:783)
at java.security.AccessController.doPrivileged(Native Method)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:774)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:755)
at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:370)
at org.eclipse.osgi.framework.internal.core.AbstractBundle.resume(AbstractBundle.java:374)
at org.eclipse.osgi.framework.internal.core.Framework.resumeBundle(Framework.java:1067)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:561)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:546)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.incFWSL(StartLevelManager.java:459)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:243)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:440)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:227)
at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:337)

Affects: 1.0.1 Fixed in: 1.1.2, 2.0.0 Votes: 0, Watches: 1

ops4j / org.ops4j.pax.web

NullpointerException in HttpServiceStarted when registering Servlet in Declarative Service with WebContainer as referenced Service [PAXWEB-313] #656