问题
I have trouble with the JVM-Heap.
We operate a website with Apache HTTP Server and an Apache Tomcat Application Server.
All *.jsp Requests to the Apache HTTP Server will be redirected to the Tomcat Server (protocol: ajp).
The website has more than 10'000 jsp files.
We have also a google search appliance and it crawle the website every night.
While it crawling, the jvm heap space rise to the max limit of 8 GB.
With javamelody, I can see that the heap space increase analogue to the loaded classes.
For the analyse I took a heapdump.
Here is the report from eclipse MAT:
One instance of "org.apache.jasper.servlet.JspServlet" loaded by "org.apache.catalina.loader.StandardClassLoader @ 0x7092c5148" occupies 1'189'603'328 (96.75%) bytes.
The memory is accumulated in one instance of "java.util.concurrent.ConcurrentHashMap$Segment[]" loaded by "".
Keywords
java.util.concurrent.ConcurrentHashMap$Segment[]
org.apache.catalina.loader.StandardClassLoader @ 0x7092c5148
org.apache.jasper.servlet.JspServlet
Is there a Problem with GSA request/s?
And why can't JVM unload the generated classes?
回答1:
It does look like loading all the JSPs is causing problems.
By default, Tomcat keeps all loaded JSPs in memory until the web application stops.
In Tomcat 7 you can set the maxLoadedJsps parameter of the JSP Servlet to limit the number of JSPs held in memory.
来源：https://stackoverflow.com/questions/10436573/jvm-heapdump-the-memory-is-accumulated-in-one-instance-of-java-util-concurrent