Getting Error number 4001 frequently

I am frequently (and randomly it seems) getting a 4001 error while parsing velocity page /templates/wysiwyginput.vm when loading pages for inline-edits.

This is happening both on fields that have wiki-syntax (2.0) content and fields that while able to take wiki-syntax content, have only plain text. (i.e. "Lengthy, detailed information as needed. A good use of this would be training for new application features. This will be limited to text. If more is needed the user should be redirected to more detailed help documentation.")

If the inline-edit page is immediately hard-refreshed (<CTRL>+<F5>), the message usually goes away and the correct content is displayed. However, users often don't notice the problem until 3-5 edits later, once the error message output has been saved to the field. (see log messages below)

The setup that I have is:
– Page
– 1 Class Object of type A w/ multiple properties (incl. several textarea fields)
– Many Class Objects of type B w/ multiple properties (incl. several textarea fields)
– Many Class Objects of type C w/ multiple properties (incl. several textarea fields)

The problem has occurred for objects from all three classes, and there doesn't seem to be any consistency as to which class/property it happens to.

The biggest thing that I can't figure out is that for one load of the page it's fine, then it's broken, then (without changing the underlying data or code) it's fine again.

Thanks!

--Matt

Here is the output from the catalina.out log file:

2010-09-09 18:12:59,874 http://xwiki.internal.nwresearch.com/xwiki/bin/preview/ProjectManagement/UseCase%2DAddEditDeleteListSystemUpdateNotifications ERROR internal.DefaultHTMLConverter - Can't find descriptor for the component [role = [org.xwiki.rendering.renderer.BlockRenderer] hint = [default]]
org.xwiki.component.manager.ComponentLookupException: Can't find descriptor for the component [role = [org.xwiki.rendering.renderer.BlockRenderer] hint = [default]]
at org.xwiki.component.embed.EmbeddableComponentManager.initialize(EmbeddableComponentManager.java:356)
at org.xwiki.component.embed.EmbeddableComponentManager.lookup(EmbeddableComponentManager.java:109)
at org.xwiki.component.internal.DefaultComponentManager.lookup(DefaultComponentManager.java:85)
at com.xpn.xwiki.wysiwyg.server.converter.internal.DefaultHTMLConverter.fromHTML(DefaultHTMLConverter.java:104)
at com.xpn.xwiki.wysiwyg.server.filter.ConversionFilter.doFilter(ConversionFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.plugin.webdav.XWikiDavFilter.doFilter(XWikiDavFilter.java:68)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.web.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:304)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:112)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
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:127)
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:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:619)
2010-09-09 18:12:59,890 http://xwiki.internal.nwresearch.com/xwiki/bin/preview/ProjectManagement/UseCase%2DAddEditDeleteListSystemUpdateNotifications ERROR filter.ConversionFilter - Exception while parsing HTML
java.lang.RuntimeException: Exception while parsing HTML
at com.xpn.xwiki.wysiwyg.server.converter.internal.DefaultHTMLConverter.fromHTML(DefaultHTMLConverter.java:110)
at com.xpn.xwiki.wysiwyg.server.filter.ConversionFilter.doFilter(ConversionFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.plugin.webdav.XWikiDavFilter.doFilter(XWikiDavFilter.java:68)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.web.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:304)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:112)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
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:127)
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:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:619)
Caused by: org.xwiki.component.manager.ComponentLookupException: Can't find descriptor for the component [role = [org.xwiki.rendering.renderer.BlockRenderer] hint = [default]]
at org.xwiki.component.embed.EmbeddableComponentManager.initialize(EmbeddableComponentManager.java:356)
at org.xwiki.component.embed.EmbeddableComponentManager.lookup(EmbeddableComponentManager.java:109)
at org.xwiki.component.internal.DefaultComponentManager.lookup(DefaultComponentManager.java:85)
at com.xpn.xwiki.wysiwyg.server.converter.internal.DefaultHTMLConverter.fromHTML(DefaultHTMLConverter.java:104)
... 22 more
org.xwiki.velocity.XWikiVelocityException: Failed to evaluate content with id [/templates/wysiwyginput.vm]
at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:200)
at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:156)
at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:116)
at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:1791)
at com.xpn.xwiki.web.Utils.parseTemplate(Utils.java:154)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:224)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:115)
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:617)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:129)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.wysiwyg.server.filter.ConversionFilter.doFilter(ConversionFilter.java:152)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.plugin.webdav.XWikiDavFilter.doFilter(XWikiDavFilter.java:68)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.web.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:304)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:112)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
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:127)
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:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:619)
Caused by: org.apache.velocity.exception.VelocityException: Reference evaluation threw an exception at /templates/wysiwyginput.vm[line 57, column 7]
at org.apache.velocity.runtime.parser.node.ASTReference.evaluate(ASTReference.java:481)
at org.apache.velocity.runtime.parser.node.ASTAndNode.evaluate(ASTAndNode.java:104)
at org.apache.velocity.runtime.parser.node.ASTExpression.evaluate(ASTExpression.java:62)
at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:85)
at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87)
at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:336)
at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:191)
... 39 more
Caused by: java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
at java.util.HashMap$EntryIterator.next(HashMap.java:834)
at java.util.HashMap$EntryIterator.next(HashMap.java:832)
at java.util.AbstractMap.toString(AbstractMap.java:485)
at org.apache.velocity.runtime.parser.node.ASTReference.evaluate(ASTReference.java:477)
... 46 more

Here is the output that displays in the field:
Error number 4001 in 4: Error while parsing velocity page /templates/wysiwyginput.vm Wrapped Exception: Failed to evaluate content with id [/templates/wysiwyginput.vm] (% id="xwikierror1" style="display: none;" %) ((( (% class="xwikierror" %) {{

{Error number 4001 in 4: Error while parsing velocity page /templates/wysiwyginput.vm Wrapped Exception: Failed to evaluate content with id [/templates/wysiwyginput.vm] com.xpn.xwiki.XWikiException: Error number 4001 in 4: Error while parsing velocity page /templates/wysiwyginput.vm Wrapped Exception: Failed to evaluate content with id [/templates/wysiwyginput.vm] at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:122) at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:1791) at com.xpn.xwiki.web.Utils.parseTemplate(Utils.java:154) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:224) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:115) 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:617) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:129) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.xpn.xwiki.wysiwyg.server.filter.ConversionFilter.doFilter(ConversionFilter.java:152) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.xpn.xwiki.plugin.webdav.XWikiDavFilter.doFilter(XWikiDavFilter.java:68) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.xpn.xwiki.web.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:304) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:112) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) 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:127) 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:298) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) at java.lang.Thread.run(Thread.java:619) Wrapped Exception: org.apache.velocity.exception.VelocityException: Reference evaluation threw an exception at /templates/wysiwyginput.vm[line 57, column 7] at org.apache.velocity.runtime.parser.node.ASTReference.evaluate(ASTReference.java:481) at org.apache.velocity.runtime.parser.node.ASTAndNode.evaluate(ASTAndNode.java:104) at org.apache.velocity.runtime.parser.node.ASTExpression.evaluate(ASTExpression.java:62) at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:85) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72) at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:336) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:191) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:156) at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:116) at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:1791) at com.xpn.xwiki.web.Utils.parseTemplate(Utils.java:154) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:224) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:115) 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:617) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:129) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.xpn.xwiki.wysiwyg.server.filter.ConversionFilter.doFilter(ConversionFilter.java:152) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.xpn.xwiki.plugin.webdav.XWikiDavFilter.doFilter(XWikiDavFilter.java:68) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.xpn.xwiki.web.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:304) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:112) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) 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:127) 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:298) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) at java.lang.Thread.run(Thread.java:619) Caused by: java.util.ConcurrentModificationException at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793) at java.util.HashMap$EntryIterator.next(HashMap.java:834) at java.util.HashMap$EntryIterator.next(HashMap.java:832) at java.util.AbstractMap.toString(AbstractMap.java:485) at org.apache.velocity.runtime.parser.node.ASTReference.evaluate(ASTReference.java:477) ... 46 more }

}} )))