Error number 4001 in 4: Error while parsing velocity page Public.RevertingCommentsOrder
Wrapped Exception: Invocation of method 'renderText' in  class com.xpn.xwiki.api.XWiki threw exception class java.lang.NullPointerException : null
com.xpn.xwiki.XWikiException: Error number 4001 in 4: Error while parsing velocity page Public.RevertingCommentsOrder
Wrapped Exception: Invocation of method 'renderText' in  class com.xpn.xwiki.api.XWiki threw exception class java.lang.NullPointerException : null
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:142)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.render(XWikiVelocityRenderer.java:98)
	at com.xpn.xwiki.render.XWikiRenderingEngine.renderText(XWikiRenderingEngine.java:208)
	at com.xpn.xwiki.render.XWikiRenderingEngine.renderText(XWikiRenderingEngine.java:131)
	at com.xpn.xwiki.render.XWikiRenderingEngine.renderDocument(XWikiRenderingEngine.java:123)
	at com.xpn.xwiki.doc.XWikiDocument.getRenderedContent(XWikiDocument.java:298)
	at com.xpn.xwiki.api.Document.getRenderedContent(Document.java:334)
	at sun.reflect.GeneratedMethodAccessor110.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:585)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:267)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:197)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:175)
	at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:220)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:230)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:234)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:136)
	at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1230)
	at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1178)
	at com.xpn.xwiki.web.Utils.parseTemplate(Utils.java:98)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:153)
	at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
	at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
	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:689)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:121)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
	at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:199)
	at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:282)
	at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:754)
	at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:684)
	at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:876)
	at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
	at java.lang.Thread.run(Thread.java:595)

Wrapped Exception:

java.lang.NullPointerException
	at com.xpn.xwiki.render.XWikiRenderingEngine.getKey(XWikiRenderingEngine.java:270)
	at com.xpn.xwiki.render.XWikiRenderingEngine.renderText(XWikiRenderingEngine.java:153)
	at com.xpn.xwiki.render.XWikiRenderingEngine.renderText(XWikiRenderingEngine.java:131)
	at com.xpn.xwiki.api.XWiki.renderText(XWiki.java:1346)
	at sun.reflect.GeneratedMethodAccessor447.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:585)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:267)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:197)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:175)
	at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:220)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:230)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:234)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:136)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.render(XWikiVelocityRenderer.java:98)
	at com.xpn.xwiki.render.XWikiRenderingEngine.renderText(XWikiRenderingEngine.java:208)
	at com.xpn.xwiki.render.XWikiRenderingEngine.renderText(XWikiRenderingEngine.java:131)
	at com.xpn.xwiki.render.XWikiRenderingEngine.renderDocument(XWikiRenderingEngine.java:123)
	at com.xpn.xwiki.doc.XWikiDocument.getRenderedContent(XWikiDocument.java:298)
	at com.xpn.xwiki.api.Document.getRenderedContent(Document.java:334)
	at sun.reflect.GeneratedMethodAccessor110.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:585)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:267)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:197)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:175)
	at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:220)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:230)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:234)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:136)
	at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1230)
	at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1178)
	at com.xpn.xwiki.web.Utils.parseTemplate(Utils.java:98)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:153)
	at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
	at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
	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:689)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:121)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
	at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:199)
	at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:282)
	at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:754)
	at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:684)
	at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:876)
	at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
	at java.lang.Thread.run(Thread.java:595)