JAMon 2.75 NPE

[Andres Salcedo]

Hi there!

Thanks for keeping up with JAMon, been a really useful tool so far!

Just to call out an odd behavior I've found in JAMon 2.75. When I'm in the admin page (HTML report) and I click on any of the checkboxes on the left of each monitored method, I get a NPE with this:

HTTP Status 500 - An exception occurred processing JSP page /monitor/monmanage.jsp at line 306

type Exception report

message An exception occurred processing JSP page /monitor/monmanage.jsp at line 306

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /monitor/monmanage.jsp at line 306

303: 
304:     private ResultSetConverter getCurrentListeners(MonKey key, String listenerType) {
305: 
306:         if (MonitorFactory.exists(key) && MonitorFactory.getMonitor(key).getListenerType(listenerType).hasListeners()) {
307:             return getCurrentListeners(MonitorFactory.getMonitor(key).getListenerType(listenerType).getListener());
308:         }
309: 


Stacktrace:
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:579)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    com.jamonapi.http.JAMonServletFilter.doFilter(JAMonServletFilter.java:49)

root cause

java.lang.NullPointerException
    org.apache.jsp.monitor.monmanage_jsp.getCurrentListeners(monmanage_jsp.java:100)
    org.apache.jsp.monitor.monmanage_jsp._jspService(monmanage_jsp.java:438)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    com.jamonapi.http.JAMonServletFilter.doFilter(JAMonServletFilter.java:49)

Hope this is of any help. I'd like to help out in any work needed (starting with Spanish translations).

[Andres Salcedo]

P.S. If I get from main JAMon page to monmanage.jsp, error shows up too.

[Steve Souza]

There is a known problem if your session times out. The way that it determines what page it should pull up is to go to your session. Currently if there is no session it causes a NPE. Could that be the problem. i.e. refresh jamonadmin.jsp and try again.

Also, jamon 2.75 is quite old. Have you tried upgrading?

Thanks for your kind words.

Steve

[Andres Salcedo]

I have this as part of my project (in Spring). I've seen it (monmanage.jsp) working once (shows some options for listener) but after a while, it throws http 500 regardless of refresh performed on jamonadmin.jsp. :(

I'll test the update to see how it goes :)

[Steve Souza]

Is there any reason why you are using 2.75? That is a very old version. I believe changes have been made to this part of the code since 2.75.

[Steve Souza]

Ok, I see you mentioned upgrading the jamon version. Let me know how that goes and I can help you further.

[Steve Souza]

Ok, I see you mentioned upgrading the jamon version. Let me know how that goes and I can help you further.

[Andres Salcedo]

Just finished testing the update to 2.81 and so far, it seems like the NPE is gone. :) I'll let it stay idle for a while before trying to click on that checkbox again.

Thanks!

[Steve Souza]

Great. Let me know if the problem reappears.