What problems can occur during the lifecycle of a Java application server?

Question

Actually i'm designing a software on top of a Java application server which must be highly available. So i also plan to include a monitoring system which will detect errors on the app server. I'll probably use JMX to do it. So what can potentially happens during the lifecyle of a Java app server? What sould i monitor?

• If a OutOfMemoryError has happened?
• If the app server has enough memory?

what else???

Thanks for replies

Answer 1

I am assuming you are mostly interested in errors related to the App Server and not the application.

The errors related to AppServer can fall under the following cat

1. Memory - These errors, as you pointed out are OutOFMemory, PermGen and so on. You can easily monitor these using JMX console or use JMX API's.
2. Network - These errors occur because of firewalls or unreliable network or network congestion. Depending on what you may need different set of tools to diagnose the issues. The outcome of network issues typically results in service unavailability, performance issues, HA failure, Cluster disintegration etc...
3. Security - These are not necessarily errors but something you need to monitor to make sure there is no breach.
4. Performance - Performance is a huge topic but in general you need to monitor resources that are critical for performance whether they are connection pools or thread pools or memory pools as these will determine how your application will perform.
5. Resource Constraints - This is where you need to understand your application better to configure enough resources to process the request. Otherwise you'll see erros. For ex: If you are expecting 100 concurrent users you need to have at least 100 threads to handle all those requests otherwise you'll start to drop the requests.

I was being very generic in identifying the potential errors in your application server. There could be more depending on your application server of choice. Also depending on your choice your monitoring tools may vary.

Hope this help.

Good luck!