This issue was first recorded in the Liferay Faces issue tracker here:
http://issues.liferay.com/browse/FACES-1598

The first time the icefaces3-portlet is loaded, it works OK. But when clicking away on a different page, and then visiting the page with the icefaces3-portlet again, the following exception occurs:

{code}
java.lang.NullPointerException
at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:768)
at org.icepush.LocalPushGroupManager.addMember(LocalPushGroupManager.java:122)
at org.icepush.PushContext.addGroupMember(PushContext.java:137)
at org.icefaces.impl.push.SessionViewManager.addView(SessionViewManager.java:51)
at org.icefaces.impl.event.BridgeSetup$2.encode(BridgeSetup.java:205)
at org.icefaces.impl.event.UIOutputWriter.encodeBegin(UIOutputWriter.java:27)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1777)
at com.liferay.faces.bridge.renderkit.html_basic.BodyRenderer.encodeEnd(BodyRenderer.java:144)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:881)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1786)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:439)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:124)
at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:286)
at com.liferay.faces.bridge.application.ViewHandlerCompatImpl.renderView(ViewHandlerCompatImpl.java:35)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at com.liferay.faces.bridge.BridgePhaseRenderImpl.execute(BridgePhaseRenderImpl.java:227)
at com.liferay.faces.bridge.BridgePhaseRenderImpl.execute(BridgePhaseRenderImpl.java:85)
at com.liferay.faces.bridge.BridgeImpl.doFacesRequest(BridgeImpl.java:112)
at javax.portlet.faces.GenericFacesPortlet.doView(GenericFacesPortlet.java:255)
at javax.portlet.GenericPortlet.doDispatch(GenericPortlet.java:328)
at javax.portlet.faces.GenericFacesPortlet.doDispatch(GenericFacesPortlet.java:204)
at javax.portlet.GenericPortlet.render(GenericPortlet.java:233)
at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:100)
at com.liferay.portal.kernel.portlet.PortletFilterUtil.doFilter(PortletFilterUtil.java:64)
at com.liferay.portal.kernel.servlet.PortletServlet.service(PortletServlet.java:111)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:301)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:72)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter.doFilter(InvokerFilter.java:73)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:527)
at weblogic.servlet.internal.RequestDispatcherImpl.include(RequestDispatcherImpl.java:447)
at com.liferay.portlet.InvokerPortletImpl.invoke(InvokerPortletImpl.java:534)
at com.liferay.portlet.InvokerPortletImpl.invokeRender(InvokerPortletImpl.java:607)
at com.liferay.portlet.InvokerPortletImpl.render(InvokerPortletImpl.java:359)
at jsp_servlet._html._portal.__render_portlet._jspService(__render_portlet.java:1252)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:301)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:72)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter.doFilter(InvokerFilter.java:73)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:527)
at weblogic.servlet.internal.RequestDispatcherImpl.include(RequestDispatcherImpl.java:447)
at com.liferay.portal.servlet.DirectServletPathRegisterDispatcher.include(DirectServletPathRegisterDispatcher.java:53)
at com.liferay.portal.servlet.PACLRequestDispatcherWrapper.doDispatch(PACLRequestDispatcherWrapper.java:90)
at com.liferay.portal.servlet.PACLRequestDispatcherWrapper.include(PACLRequestDispatcherWrapper.java:54)
at com.liferay.portal.util.PortalImpl.renderPortlet(PortalImpl.java:5158)
at com.liferay.portal.util.PortalUtil.renderPortlet(PortalUtil.java:1569)
at com.liferay.portlet.layoutconfiguration.util.RuntimePortletImpl.processPortlet(RuntimePortletImpl.java:165)
at com.liferay.portlet.layoutconfiguration.util.RuntimePortletImpl.processPortlet(RuntimePortletImpl.java:97)
at com.liferay.portlet.layoutconfiguration.util.RuntimePortletImpl.doProcessTemplate(RuntimePortletImpl.java:531)
at com.liferay.portlet.layoutconfiguration.util.RuntimePortletImpl.doDispatch(RuntimePortletImpl.java:394)
at com.liferay.portlet.layoutconfiguration.util.RuntimePortletImpl.processTemplate(RuntimePortletImpl.java:228)
at com.liferay.portlet.layoutconfiguration.util.RuntimePortletImpl.processTemplate(RuntimePortletImpl.java:216)
at com.liferay.portlet.layoutconfiguration.util.RuntimePortletUtil.processTemplate(RuntimePortletUtil.java:113)
at jsp_servlet._html._portal._layout._view.__portlet._jspService(__portlet.java:522)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:301)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:72)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter.doFilter(InvokerFilter.java:73)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:527)
at weblogic.servlet.internal.RequestDispatcherImpl.include(RequestDispatcherImpl.java:447)
at com.liferay.portal.action.LayoutAction.includeLayoutContent(LayoutAction.java:468)
at com.liferay.portal.action.LayoutAction.processLayout(LayoutAction.java:735)
at com.liferay.portal.action.LayoutAction.execute(LayoutAction.java:249)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at com.liferay.portal.struts.PortalRequestProcessor.process(PortalRequestProcessor.java:176)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at com.liferay.portal.servlet.MainServlet.callParentService(MainServlet.java:560)
at com.liferay.portal.servlet.MainServlet.service(MainServlet.java:537)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:301)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:72)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
at com.liferay.portal.servlet.filters.secure.SecureFilter.processFilter(SecureFilter.java:294)
at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter.doFilter(InvokerFilter.java:73)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:527)
at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:253)
at com.liferay.portal.servlet.FriendlyURLServlet.service(FriendlyURLServlet.java:138)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:301)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:72)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
at com.liferay.portal.servlet.filters.strip.StripFilter.processFilter(StripFilter.java:335)
at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
at com.liferay.portal.servlet.filters.secure.SecureFilter.processFilter(SecureFilter.java:294)
at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
at com.liferay.portal.servlet.filters.i18n.I18nFilter.processFilter(I18nFilter.java:241)
at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
at com.liferay.portal.servlet.filters.autologin.AutoLoginFilter.processFilter(AutoLoginFilter.java:253)
at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
at com.liferay.portal.servlet.filters.sso.ntlm.NtlmPostFilter.processFilter(NtlmPostFilter.java:83)
at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
at com.liferay.portal.sharepoint.SharepointFilter.processFilter(SharepointFilter.java:80)
at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
at com.liferay.portal.servlet.filters.virtualhost.VirtualHostFilter.processFilter(VirtualHostFilter.java:216)
at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDirectCallFilter(InvokerFilterChain.java:187)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:95)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:738)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDirectCallFilter(InvokerFilterChain.java:167)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:95)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDirectCallFilter(InvokerFilterChain.java:167)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:95)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDirectCallFilter(InvokerFilterChain.java:187)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:95)
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter.doFilter(InvokerFilter.java:73)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3730)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3696)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2273)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2179)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1490)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:256)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)
{code}

The workaround for the icefaces3-portlet is to exclude the icepush.jar dependency with a maven profile, since the portlet does not make use of Ajax Push functionality:

{code}
<profile>
<id>weblogic</id>
<dependencies>
<dependency>
<groupId>org.icefaces</groupId>
<artifactId>icefaces</artifactId>
<exclusions>
<exclusion>
<groupId>org.icepush</groupId>
<artifactId>icepush</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
</profile>
{code}