Periodic NullPointerException

mark.butler · January 9, 2018, 1:59pm

Hi,

Periodically a NullPointerException message appears when the Cuba application is open in the browser. Looking at the logs I can see the following Exception:

    09:05:02.238 ERROR com.haulmont.cuba.web.log.AppLog - Exception: 
java.lang.NullPointerException
	at org.apache.catalina.connector.Request.notifyAttributeRemoved(Request.java:1599)
	at org.apache.catalina.connector.Request.removeAttribute(Request.java:1477)
	at org.apache.catalina.connector.RequestFacade.removeAttribute(RequestFacade.java:552)
	at javax.servlet.ServletRequestWrapper.removeAttribute(ServletRequestWrapper.java:261)
	at org.atmosphere.cpr.AtmosphereRequest.removeAttribute(AtmosphereRequest.java:749)
	at org.atmosphere.container.Servlet30CometSupport.endAsyncContext(Servlet30CometSupport.java:132)
	at org.atmosphere.container.Servlet30CometSupport.complete(Servlet30CometSupport.java:117)
	at org.atmosphere.container.Servlet30CometSupport.complete(Servlet30CometSupport.java:44)
	at org.atmosphere.cpr.AtmosphereResourceImpl.cancel(AtmosphereResourceImpl.java:762)
	at org.atmosphere.cpr.AtmosphereResourceImpl.dirtyClose(AtmosphereResourceImpl.java:868)
	at org.atmosphere.cpr.DefaultBroadcaster.addAtmosphereResource(DefaultBroadcaster.java:1429)
	at org.atmosphere.cpr.AtmosphereResourceImpl.suspend(AtmosphereResourceImpl.java:407)
	at com.vaadin.server.communication.PushHandler.suspend(PushHandler.java:180)
	at com.vaadin.server.communication.PushHandler$1.run(PushHandler.java:105)
	at com.vaadin.server.communication.PushHandler.callWithUi(PushHandler.java:240)
	at com.vaadin.server.communication.PushHandler.onConnect(PushHandler.java:483)
	at com.vaadin.server.communication.PushAtmosphereHandler.onConnect(PushAtmosphereHandler.java:99)
	at com.vaadin.server.communication.PushAtmosphereHandler.onRequest(PushAtmosphereHandler.java:75)
	at org.atmosphere.cpr.AsynchronousProcessor.action(AsynchronousProcessor.java:199)
	at org.atmosphere.cpr.AsynchronousProcessor.suspended(AsynchronousProcessor.java:107)
	at org.atmosphere.container.Servlet30CometSupport.service(Servlet30CometSupport.java:66)
	at org.atmosphere.cpr.AtmosphereFramework.doCometSupport(AtmosphereFramework.java:2075)
	at com.vaadin.server.communication.PushRequestHandler.handleRequest(PushRequestHandler.java:248)
	at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1436)
	at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:385)
	at com.haulmont.cuba.web.sys.CubaApplicationServlet.serviceAppRequest(CubaApplicationServlet.java:301)
	at com.haulmont.cuba.web.sys.CubaApplicationServlet.service(CubaApplicationServlet.java:192)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at com.haulmont.cuba.web.sys.CubaHttpFilter.handleNotFiltered(CubaHttpFilter.java:108)
	at com.haulmont.cuba.web.sys.CubaHttpFilter.doFilter(CubaHttpFilter.java:95)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:639)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:748)

I do also see these messages (not sure if related or not):

09:05:09.139 WARN  o.atmosphere.cpr.DefaultBroadcaster - Duplicate resource 81bec77b-3a09-4574-92f5-d5edef5c6571. Could be caused by a dead connection not detected by your server. Replacing the old one with the fresh one
09:05:09.140 WARN  c.h.c.web.sys.CubaApplicationServlet - Too long request processing [10823 ms]: ip=172.17.0.1, url=/app/UIDL/
09:05:13.319 WARN  o.atmosphere.cpr.DefaultBroadcaster - Duplicate resource 1b87bd61-6ec6-4bdc-a9e5-9a207ce2563e. Could be caused by a dead connection not detected by your server. Replacing the old one with the fresh one
09:05:24.322 WARN  o.atmosphere.cpr.DefaultBroadcaster - Duplicate resource 0c25692d-a321-43e2-8117-87bd0e5e4e94. Could be caused by a dead connection not detected by your server. Replacing the old one with the fresh one
09:05:24.655 WARN  c.h.c.web.sys.CubaApplicationServlet - Too long request processing [6223 ms]: ip=172.17.0.1, url=/app/UIDL/
09:05:25.682 WARN  o.atmosphere.cpr.DefaultBroadcaster - Duplicate resource dda5a968-2cd0-4bce-9b02-6c540f4afb86. Could be caused by a dead connection not detected by your server. Replacing the old one with the fresh one
09:05:27.859 WARN  o.atmosphere.cpr.DefaultBroadcaster - Duplicate resource 6c244625-fbe4-4056-ba3d-9b264e4c8b08. Could be caused by a dead connection not detected by your server. Replacing the old one with the fresh one

Does anyone know why these occur?

gorelov · January 9, 2018, 3:14pm

Hi,

Do you use a proxy server to access your application?

Regards,
Gleb

mark.butler · January 9, 2018, 3:15pm

Hi Gleb,

The application is hosted in Amazon Web Services and I use a loadbalancer (HTTPS enabled) and that redirects to Apache which in turn redirects to a Docker instance of the application.

Thanks

gorelov · January 9, 2018, 3:21pm

Thank you for reporting the problem. I need to do some investigation to find a solution.

Regards,
Gleb

gorelov · January 11, 2018, 2:51pm

Hi,

I reproduced the problem. The solution is to set proxy-server options as described in the documentation.

Regards,
Gleb

mark.butler · January 30, 2018, 6:26pm

Hi Gleb,

Do I set the proxy options in the .properties file or the DB?

Many thanks

gorelov · February 2, 2018, 6:55am

Hi,

Proxy options should be set in the nginx configuration file, by default it’s nginx.conf.

mark.butler · February 18, 2018, 8:33am

Hi Gleb,

Sorry I’m still a bit stuck on this one - I can’t find too much information on where the nginx.conf file should be located or the general format of it?

I’m not actually using nginx as a proxy - does that matter?

Many thanks

gorelov · February 19, 2018, 7:25am

Hi,

Take a look at this topic. Since version 6.8.0, we implemented the cuba.web.pushLongPollingSuspendTimeoutMs parameter that can be helpfull for you.