I attempted to edit the CalendarEvent Class by changing the Start Date and End Date format from: dd/MM/yyyy to: MM/dd/yyyy when I clicked Save & View I got this exception - I get the same exception if I attempt to rollback to a previous version? Any idea what causes this problem or how to fix it. Error number 3201 in 3: Exception while saving document XWiki.CalendarEvent Wrapped Exception: Error number 3211 in 3: Exception while updating archive XWiki.CalendarEvent Wrapped Exception: Error number 13027 in 13: Failed to create diff for doc XWiki.CalendarEvent Wrapped Exception: null com.xpn.xwiki.XWikiException: Error number 3201 in 3: Exception while saving document XWiki.CalendarEvent Wrapped Exception: Error number 3211 in 3: Exception while updating archive XWiki.CalendarEvent Wrapped Exception: Error number 13027 in 13: Failed to create diff for doc XWiki.CalendarEvent Wrapped Exception: null at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc(XWikiHibernateStore.java:457) at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:97) at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:91) at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1078) at com.xpn.xwiki.web.PropUpdateAction.propUpdate(PropUpdateAction.java:79) at com.xpn.xwiki.web.SaveAndContinueAction.action(SaveAndContinueAction.java:59) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:188) 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.doPost(ActionServlet.java:432) at javax.servlet.http.HttpServlet.service(HttpServlet.java:710) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151) at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:200) at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:283) at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:773) at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:703) at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:895) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689) at java.lang.Thread.run(Thread.java:595) Wrapped Exception: com.xpn.xwiki.XWikiException: Error number 3211 in 3: Exception while updating archive XWiki.CalendarEvent Wrapped Exception: Error number 13027 in 13: Failed to create diff for doc XWiki.CalendarEvent Wrapped Exception: null at com.xpn.xwiki.store.XWikiHibernateVersioningStore.updateXWikiDocArchive(XWikiHibernateVersioningStore.java:203) at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc(XWikiHibernateStore.java:332) at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:97) at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:91) at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1078) at com.xpn.xwiki.web.PropUpdateAction.propUpdate(PropUpdateAction.java:79) at com.xpn.xwiki.web.SaveAndContinueAction.action(SaveAndContinueAction.java:59) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:188) 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.doPost(ActionServlet.java:432) at javax.servlet.http.HttpServlet.service(HttpServlet.java:710) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151) at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:200) at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:283) at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:773) at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:703) at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:895) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689) at java.lang.Thread.run(Thread.java:595) Wrapped Exception: com.xpn.xwiki.XWikiException: Error number 13027 in 13: Failed to create diff for doc XWiki.CalendarEvent Wrapped Exception: null at com.xpn.xwiki.doc.rcs.XWikiPatch.setDiffVersion(XWikiPatch.java:176) at com.xpn.xwiki.doc.rcs.XWikiPatch.setDiffVersion(XWikiPatch.java:153) at com.xpn.xwiki.doc.XWikiDocumentArchive.makePatch(XWikiDocumentArchive.java:140) at com.xpn.xwiki.doc.XWikiDocumentArchive.updateArchive(XWikiDocumentArchive.java:255) at com.xpn.xwiki.store.XWikiHibernateVersioningStore.updateXWikiDocArchive(XWikiHibernateVersioningStore.java:198) at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc(XWikiHibernateStore.java:332) at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:97) at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:91) at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1078) at com.xpn.xwiki.web.PropUpdateAction.propUpdate(PropUpdateAction.java:79) at com.xpn.xwiki.web.SaveAndContinueAction.action(SaveAndContinueAction.java:59) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:188) 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.doPost(ActionServlet.java:432) at javax.servlet.http.HttpServlet.service(HttpServlet.java:710) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151) at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:200) at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:283) at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:773) at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:703) at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:895) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689) at java.lang.Thread.run(Thread.java:595) Wrapped Exception: java.lang.NullPointerException -- View this message in context: http://www.nabble.com/CalendarEvent----Failed-to-create-diff-tp17190022p171… Sent from the XWiki- Dev mailing list archive at Nabble.com.