Details
- 
    Bug 
- 
    Resolution: Fixed
- 
    Major 
- 
    10.11, 11.0
- 
    Windows 10 Pro 64 bit, Chrome 71, using a local instance XWiki 10.11.2 on MySQL 5.7
- 
        Unknown
- 
        N/A
- 
        N/A
- 
        
Description
STEPS TO REPRODUCE:
- Log in as Admin
- Go to Administer Wiki > Look & Feel > Panels > Page Layout Tab
- Set the 'Panels displayed on the right' to 'Panels.Applications'
- Click 'Save'
- Go to http://127.0.0.1:8080/xwiki/bin/edit/Panels/Applications?&force=1 and click "Save&View"
EXPECTED RESULTS
The panel 'Panels.Applications' is properly displayed on the right side column.
ACTUAL RESULTS:
An error is displayed in the panel's place:
Failed to execute UIX with id [xwiki:Panels.Applications]. Cause: [null]. Click on this message for details.
Here is the contained stacktrace:
java.lang.NullPointerException
	at org.xwiki.rendering.async.internal.block.DefaultBlockAsyncRendererExecutor.execute(DefaultBlockAsyncRendererExecutor.java:138)
	at org.xwiki.rendering.async.internal.block.DefaultBlockAsyncRendererExecutor.execute(DefaultBlockAsyncRendererExecutor.java:107)
	at org.xwiki.uiextension.internal.AbstractWikiUIExtension.execute(AbstractWikiUIExtension.java:112)
	at sun.reflect.GeneratedMethodAccessor211.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:395)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:384)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:173)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280)
	at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:567)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:151)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280)
	at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:369)
	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.ASTBlock.render(ASTBlock.java:72)
	at org.apache.velocity.runtime.directive.Foreach.render(Foreach.java:420)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207)
	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:342)
	at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluateInternal(DefaultVelocityEngine.java:259)
	at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:222)
	at com.xpn.xwiki.render.DefaultVelocityManager.evaluate(DefaultVelocityManager.java:358)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.evaluateContent(InternalTemplateManager.java:847)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:723)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.lambda$renderFromSkin$0(InternalTemplateManager.java:698)
	at com.xpn.xwiki.internal.security.authorization.DefaultAuthorExecutor.call(DefaultAuthorExecutor.java:98)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:697)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:676)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:662)
	at com.xpn.xwiki.internal.template.DefaultTemplateManager.render(DefaultTemplateManager.java:78)
	at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:2290)
	at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:2268)
	at com.xpn.xwiki.api.XWiki.parseTemplate(XWiki.java:992)
	at sun.reflect.GeneratedMethodAccessor190.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:395)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:384)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:173)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280)
	at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:369)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:216)
	at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:311)
	at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:230)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342)
	at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluateInternal(DefaultVelocityEngine.java:259)
	at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:222)
	at com.xpn.xwiki.render.DefaultVelocityManager.evaluate(DefaultVelocityManager.java:358)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.evaluateContent(InternalTemplateManager.java:847)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:723)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.lambda$renderFromSkin$0(InternalTemplateManager.java:698)
	at com.xpn.xwiki.internal.security.authorization.DefaultAuthorExecutor.call(DefaultAuthorExecutor.java:98)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:697)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:676)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:662)
	at com.xpn.xwiki.internal.template.DefaultTemplateManager.render(DefaultTemplateManager.java:78)
	at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:2290)
	at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:2268)
	at com.xpn.xwiki.api.XWiki.parseTemplate(XWiki.java:992)
	at sun.reflect.GeneratedMethodAccessor190.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:395)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:384)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:173)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280)
	at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:369)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:216)
	at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:311)
	at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:230)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342)
	at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluateInternal(DefaultVelocityEngine.java:259)
	at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:222)
	at com.xpn.xwiki.render.DefaultVelocityManager.evaluate(DefaultVelocityManager.java:358)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.evaluateContent(InternalTemplateManager.java:847)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:723)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.lambda$renderFromSkin$0(InternalTemplateManager.java:698)
	at com.xpn.xwiki.internal.security.authorization.DefaultAuthorExecutor.call(DefaultAuthorExecutor.java:98)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:697)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:676)
	at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:662)
	at com.xpn.xwiki.internal.template.DefaultTemplateManager.render(DefaultTemplateManager.java:78)
	at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:2290)
	at com.xpn.xwiki.web.Utils.parseTemplate(Utils.java:179)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:489)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:210)
	at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:425)
	at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:228)
	at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
	at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:860)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1650)
	at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:112)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
	at org.xwiki.wysiwyg.filter.ConversionFilter.doFilter(ConversionFilter.java:109)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
	at org.xwiki.container.servlet.filters.internal.SetHTTPHeaderFilter.doFilter(SetHTTPHeaderFilter.java:63)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
	at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:208)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
	at org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:111)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
	at org.xwiki.resource.servlet.RoutingFilter.doFilter(RoutingFilter.java:134)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1629)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:190)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:188)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1253)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:168)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:166)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1155)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:219)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.Server.handle(Server.java:530)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:347)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:256)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:279)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102)
	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:124)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:247)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce(EatWhatYouKill.java:140)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:131)
	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:382)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:708)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:626)
	at java.lang.Thread.run(Unknown Source)
If the page is refreshed several times, the panel is displayed properly. It seems the error is displayed every time after the panels configuration is saved and/or if the XWiki instance is restarted. No errors in console.
The issue could not be reproduced on XWiki 10.10.
