Using an .ear containing an ICEfaces 2 application on WebLogic Server results in the following exception when trying to start the application:

####<May 18, 2011 12:19:50 AM CEST> <Warning> <HTTP> <stand-alone.o-net.domain> <ICEsoft_Stand-Alone_Server> <[ACTIVE] ExecuteThread: '3' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <> <> <1305670790655> <BEA-101162> <User defined listener
 org.icepush.servlet.MainServlet$ExtensionRegistration failed: java.lang.NullPointerException.
java.lang.NullPointerException
        at org.icepush.util.ExtensionRegistry.addExtension(ExtensionRegistry.java:52)
        at org.icepush.servlet.MainServlet$ExtensionRegistration.contextInitialized(MainServlet.java:125)
        at weblogic.servlet.internal.EventsManager$FireContextListenerAction.run(EventsManager.java:481)
        at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
        at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
        at weblogic.servlet.internal.EventsManager.notifyContextCreatedEvent(EventsManager.java:181)
        at weblogic.servlet.internal.WebAppServletContext.preloadResources(WebAppServletContext.java:1872)
        at weblogic.servlet.internal.WebAppServletContext.start(WebAppServletContext.java:3153)
        at weblogic.servlet.internal.WebAppModule.startContexts(WebAppModule.java:1508)
        at weblogic.servlet.internal.WebAppModule.start(WebAppModule.java:482)
        at weblogic.application.internal.flow.ModuleStateDriver$3.next(ModuleStateDriver.java:425)
        at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:52)
        at weblogic.application.internal.flow.ModuleStateDriver.start(ModuleStateDriver.java:119)
        at weblogic.application.internal.flow.ScopedModuleDriver.start(ScopedModuleDriver.java:200)
        at weblogic.application.internal.flow.ModuleListenerInvoker.start(ModuleListenerInvoker.java:247)
        at weblogic.application.internal.flow.ModuleStateDriver$3.next(ModuleStateDriver.java:425)
        at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:52)
        at weblogic.application.internal.flow.ModuleStateDriver.start(ModuleStateDriver.java:119)
        at weblogic.application.internal.flow.StartModulesFlow.activate(StartModulesFlow.java:27)
        at weblogic.application.internal.BaseDeployment$2.next(BaseDeployment.java:636)
        at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:52)
        at weblogic.application.internal.BaseDeployment.activate(BaseDeployment.java:205)
        at weblogic.application.internal.EarDeployment.activate(EarDeployment.java:58)
        at weblogic.application.internal.DeploymentStateChecker.activate(DeploymentStateChecker.java:161)
        at weblogic.deploy.internal.targetserver.AppContainerInvoker.activate(AppContainerInvoker.java:79)
        at weblogic.deploy.internal.targetserver.operations.AbstractOperation.activate(AbstractOperation.java:569)
        at weblogic.deploy.internal.targetserver.operations.ActivateOperation.activateDeployment(ActivateOperation.java:150)
        at weblogic.deploy.internal.targetserver.operations.ActivateOperation.doCommit(ActivateOperation.java:116)
        at weblogic.deploy.internal.targetserver.operations.AbstractOperation.commit(AbstractOperation.java:323)
        at weblogic.deploy.internal.targetserver.DeploymentManager.handleDeploymentCommit(DeploymentManager.java:844)
        at weblogic.deploy.internal.targetserver.DeploymentManager.activateDeploymentList(DeploymentManager.java:1253)
        at weblogic.deploy.internal.targetserver.DeploymentManager.handleCommit(DeploymentManager.java:440)
        at weblogic.deploy.internal.targetserver.DeploymentServiceDispatcher.commit(DeploymentServiceDispatcher.java:163)
        at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer.doCommitCallback(DeploymentReceiverCallbackDeliverer.java:195)
        at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer.access$100(DeploymentReceiverCallbackDeliverer.java:13)
        at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer$2.run(DeploymentReceiverCallbackDeliverer.java:68)
        at weblogic.work.SelfTuningWorkManagerImpl$WorkAdapterImpl.run(SelfTuningWorkManagerImpl.java:528)
        at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209)
        at weblogic.work.ExecuteThread.run(ExecuteThread.java:178)
>

This seems to be related to the following code snippets from the ExtensionRegistry class"

    public void contextInitialized(ServletContextEvent servletContextEvent) {
        servletContextEvent.getServletContext().setAttribute(NAME, new HashMap());
    }

    public static void addExtension(ServletContext context, int quality, String name, Object extension) {
        Map extensions = (Map) context.getAttribute(NAME);
        TreeSet namedExtensions = (TreeSet) extensions.get(name); <===--- NPE
        if (namedExtensions == null) {
            namedExtensions = new TreeSet();
            extensions.put(name, namedExtensions);
        }

        namedExtensions.add(new ExtensionEntry(quality, extension));
    }