After trying delete a war (unsuccessfully), and staying at the history page for a while,
the following error occured.

May be related to Bug 687983 - NPE during faces rendering (edit) 

2011-03-14 14:30:19,623 ERROR [org.rhq.enterprise.gui.common.error.GenericErrorUIBean] Error processing user request
javax.faces.FacesException: javax.faces.FacesException: javax.el.ELException: /rhq/resource/content/audit-trail-item.xhtml @36,105 rendered="#{!empty AuditTrailItemUIBean.history.packageVersion.displayName}": Error reading 'history' on type org.rhq.enterprise.gui.content.AuditTrailItemUIBean
at javax.faces.component.UIComponent.invokeOnComponent(UIComponent.java:714)
at javax.faces.component.UIComponentBase.invokeOnComponent(UIComponentBase.java:675)
at javax.faces.component.UIComponent.invokeOnComponent(UIComponent.java:720)
at javax.faces.component.UIComponentBase.invokeOnComponent(UIComponentBase.java:675)
at javax.faces.component.UIComponent.invokeOnComponent(UIComponent.java:720)
at javax.faces.component.UIComponentBase.invokeOnComponent(UIComponentBase.java:675)
at javax.faces.component.UIComponent.invokeOnComponent(UIComponent.java:720)
at javax.faces.component.UIComponentBase.invokeOnComponent(UIComponentBase.java:675)
at org.ajax4jsf.component.AjaxViewRoot.encodeChildren(AjaxViewRoot.java:551)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:930)
at com.sun.facelets.FaceletViewHandler.renderView(FaceletViewHandler.java:592)
at org.rhq.enterprise.gui.common.framework.FaceletRedirectionViewHandler.renderView(FaceletRedirectionViewHandler.java:64)
at org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:100)
at org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:176)
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.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:530)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.rhq.enterprise.gui.legacy.WebUserTrackingFilter.doFilter(WebUserTrackingFilter.java:50)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.rhq.enterprise.gui.legacy.AuthenticationFilter.doFilter(AuthenticationFilter.java:129)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.rhq.enterprise.gui.common.upload.MultipartFilter.doFilter(MultipartFilter.java:63)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83)
at org.jboss.seam.web.IdentityFilter.doFilter(IdentityFilter.java:40)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:90)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:206)
at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388)
at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515)
at org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:56)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:60)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.HotDeployFilter.doFilter(HotDeployFilter.java:53)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.rhq.helpers.rtfilter.filter.RtFilter.doFilter(RtFilter.java:124)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
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:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:173)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:182)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:241)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
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(Thread.java:662)
Caused by: javax.faces.FacesException: javax.el.ELException: /rhq/resource/content/audit-trail-item.xhtml @36,105 rendered="#{!empty AuditTrailItemUIBean.history.packageVersion.displayName}": Error reading 'history' on type org.rhq.enterprise.gui.content.AuditTrailItemUIBean
at javax.faces.component.UIComponentBase.isRendered(UIComponentBase.java:393)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:111)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxChildren(AjaxChildrenRenderer.java:83)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:157)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxChildren(AjaxChildrenRenderer.java:83)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:157)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxChildren(AjaxChildrenRenderer.java:83)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:157)
at org.ajax4jsf.renderkit.AjaxContainerRenderer.encodeAjax(AjaxContainerRenderer.java:124)
at org.ajax4jsf.component.UIAjaxRegion.encodeAjax(UIAjaxRegion.java:263)
at org.ajax4jsf.component.AjaxViewRoot$4.invokeContextCallback(AjaxViewRoot.java:497)
at javax.faces.component.UIComponent.invokeOnComponent(UIComponent.java:711)
... 72 more
Caused by: javax.el.ELException: /rhq/resource/content/audit-trail-item.xhtml @36,105 rendered="#{!empty AuditTrailItemUIBean.history.packageVersion.displayName}": Error reading 'history' on type org.rhq.enterprise.gui.content.AuditTrailItemUIBean
at com.sun.facelets.el.TagValueExpression.getValue(TagValueExpression.java:76)
at javax.faces.component.UIComponentBase.isRendered(UIComponentBase.java:390)
... 83 more
Caused by: java.lang.NumberFormatException: null
at java.lang.Integer.parseInt(Integer.java:417)
at java.lang.Integer.parseInt(Integer.java:499)
at org.rhq.enterprise.gui.content.AuditTrailItemUIBean.getSelectedHistoryId(AuditTrailItemUIBean.java:53)
at org.rhq.enterprise.gui.content.AuditTrailItemUIBean.getHistory(AuditTrailItemUIBean.java:40)
at sun.reflect.GeneratedMethodAccessor2186.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:62)
at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:53)
at com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:72)
at org.jboss.el.parser.AstPropertySuffix.getValue(AstPropertySuffix.java:53)
at org.jboss.el.parser.AstValue.getValue(AstValue.java:67)
at org.jboss.el.parser.AstEmpty.getValue(AstEmpty.java:29)
at org.jboss.el.parser.AstNot.getValue(AstNot.java:26)
at org.jboss.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
at com.sun.facelets.el.TagValueExpression.getValue(TagValueExpression.java:71)
... 84 more