将myfaces 2.2与apache tile集成时，我遇到了错误
java.lang.NullPointerException
at org.apache.myfaces.view.facelets.FaceletViewDeclarationLanguage.createView(FaceletViewDeclarationLanguage.java:2055)
at org.apache.myfaces.application.ViewHandlerImpl.createView(ViewHandlerImpl.java:262)
at javax.faces.application.ViewHandlerWrapper.createView(ViewHandlerWrapper.java:100)
at org.apache.myfaces.tomahawk.application.ResourceViewHandlerWrapper.createView(ResourceViewHandlerWrapper.java:70)
at org.apache.myfaces.tomahawk.application.jsp.JspTilesTwoViewHandlerImpl.createView(JspTilesTwoViewHandlerImpl.java:547)
at org.apache.myfaces.lifecycle.RestoreViewExecutor.execute(RestoreViewExecutor.java:289)
at org.apache.myfaces.lifecycle.LifecycleImpl.executePhase(LifecycleImpl.java:196)
at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:143)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:198)
at org.apache.myfaces.webapp.MyFacesServlet.service(MyFacesServlet.java:112)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:286)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:260)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:137)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:350)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:25)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:78)
at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:357)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:78)
at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:32)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:78)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3701)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3667)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:326)
at weblogic.security.service.SecurityManager.runAsForUserCode(SecurityManager.java:197)
at weblogic.servlet.provider.WlsSecurityProvider.runAsForUserCode(WlsSecurityProvider.java:203)
at weblogic.servlet.provider.WlsSubjectHandle.run(WlsSubjectHandle.java:71)
at weblogic.servlet.internal.WebAppServletContext.doSecuredExecute(WebAppServletContext.java:2443)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2291)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2269)
at weblogic.servlet.internal.ServletRequestImpl.runInternal(ServletRequestImpl.java:1705)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1665)
at weblogic.servlet.provider.ContainerSupportProviderImpl$WlsRequestExecutor.run(ContainerSupportProviderImpl.java:272)
at weblogic.invocation.ComponentInvocationContextManager._runAs(ComponentInvocationContextManager.java:352)
at weblogic.invocation.ComponentInvocationContextManager.runAs(ComponentInvocationContextManager.java:337)
at weblogic.work.LivePartitionUtility.doRunWorkUnderContext(LivePartitionUtility.java:57)
at weblogic.work.PartitionUtility.runWorkUnderContext(PartitionUtility.java:41)
at weblogic.work.SelfTuningWorkManagerImpl.runWorkUnderContext(SelfTuningWorkManagerImpl.java:652)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:420)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:360)
我正在尝试使用Apache磁贴，并在tile-def.xml中指定了布局。在应用程序的web.xml中添加相同的内容。
<context-param>
<param-name>tiles-definitions</param-name>
<param-value>/WEB-INF/tiles-defs.xml</param-value>
</context-param>
我的主页位于maven结构app / folderstructure（a / b）下。
但是它抛出了错误。