Some users complain about NPE
SEVERE: Servlet.service() for servlet Faces Servlet threw exception
 java.lang.NullPointerException
  at com.sun.faces.renderkit.RenderKitImpl.createResponseWriter(RenderKitImpl.java:188)
  at com.icesoft.faces.renderkit.D2DRenderKit.createResponseWriter(D2DRenderKit.java:82)
  at com.sun.faces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:189)
  at com.icesoft.faces.application.D2DViewHandler.renderView(D2DViewHandler.java:145)
  at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:110)
  at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:100)
  at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
  at javax.faces.webapp.FacesServlet.service(FacesServlet.java:266)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
  at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
  at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
  at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
  at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
  at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
  at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
  at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
  at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
  at java.lang.Thread.run(Unknown Source)

from forum posts as
http://www.icefaces.org/JForum/posts/list/12908.page
http://www.icefaces.org/JForum/posts/list/13054.page

This is caused by issuing wrong url. http://xxxx/xx.jsf, which is handled by faces servlet instead of persistent faces servlet.

In ICEfaces 1.8 for Eclipse 3.4 release, a logic of changing url mappings defined for Faces Servlet to Persistent Faces Servlet was removed to support a special case. Appearently it was wrong decision and I will put the logic back in upcoming ICEfaces v1.8.1 release

extend FileURL extension should be revisited as well even though there are side effect with it.