MSGAlert connection problems
Some people reported the other day that they were having problems connecting to MSGAlert – we thought to start with it might just be a firewall issue – the port it runs on might have been blocked by their firewall, but after a bit of investigation we found out what the problem really was.
We were getting errors like these appearing in out tomcat log files:
INFO: Illegal access: this web application instance has been stopped already. Could not load META-INF/services/javax.xml.parsers.DocumentBuilderFactory. The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
INFO: Illegal access: this web application instance has been stopped already. Could not load com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl. The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
INFO: Illegal access: this web application instance has been stopped already. Could not load com.sun.org.apache.xerces.internal.impl.dv.dtd.DTDDVFactoryImpl. The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
For most of the afternoon we pretty pretty stumped as to the cause – mainly thinking there was a jar file missing or something – but that didn’t seem right as the same code was being used in other places and ran fine. It was also odd that it ran fine on Windows, but not on Linux, but it had (until recently) been working fine on Linux too.
The cause turned out to be that there were 2 tomcat processes running, when the server-side code is running for MSGAlert it listens on port 5225, the ‘old’ process had control of the port, but the old prcoesses servlet container wasn’t running – but this meant the port wasn’t available for the correct container to use – hence the error.
Once we’d stopped (killed) all the tomcat processes and restarted (just the one!) all started to work fine.
Thought I should post this up as we had quite a job finding any useful information on Google about the errors we were getting, even though it appears quite a lot of people come across the same issue 
