Javamelody is an opensource (LGPL) application to monitor Java or Java EE application servers in QA and production environments.
JavaMelody is mainly based on statistics of requests and on evolution charts.
It allows to improve applications in QA and production and helps to:
• give facts about the average response times and number of executions
• make decisions when trends are bad, before problems become too serious
• optimize based on the more limiting response times
• find the root causes of response times
• verify the real improvement after optimizations
It includes summary charts showing the evolution over time of the following indicators:
• Number of executions, mean execution times and percentage of errors of http requests, sql requests, jsp pages or methods of business façades (if EJB3, Spring or Guice)
• Java memory
• Java CPU
• Number of user sessions
• Number of jdbc connections
These charts can be viewed on the current day, week, month, year or custom period.
You can even execute garbage collection to free resources, or view / invalidate http sessions.
Setting up javamelody on your server.
Step 1:
Download the javamelody-1.36.0.zip zip file.
Now, unzip, and add copy the files javamelody.jar and jrobin-x.jar into the in the lib directory of Tomcat.
Now, add the following lines in the web.xml file of the conf directory of Tomcat (and not in the WEB-INF/web.xml files of the webapps).
<filter>
<filter-name>monitoring</filter-name>
<filter-class>net.bull.javamelody.MonitoringFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>monitoring</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<listener>
<listener-class>net.bull.javamelody.SessionListener</listener-class>
</listener>
Once this is done, all you need to do is restart the application. Once the application is up, navigate to http://<host>/<context>/monitoring url to view a whole set of interesting data.
The full instrcutions are available here.