Memory leak in a Java web application

Question

I have a Java web application running on Tomcat 7 that appears to have a memory leak. The average memory usage of the application increases linearly over time when under load (d

Answer 1

I can recommend jvisualvm which comes along with every Java installation. Start the programm, connect to your Webapplication. Go to Monitor -> Heap Dump. It now may take some time (depending on the size). The navigation through the Heap Dump is quite easy, but the meaning you have to figure out yourself (not too complicated though), e.g.

Go to Classes (within the heapdump), select java.lang.String, right click Show in Instances View. After that you'll see on the left side table String instances currently active in your system. Klick on one String instance and you'll see some String preferenes on the right-upper part of the right table, like the value of the String.

On the bottom-right part of the right table you'll see where this String instance is referenced from. Here you have to check where the most of your *String*s are being referenced from. But with your case (176/210, good propability to find some String examples which causes your problems soon) it should be clear after some inspection where the problem lies.