PermGen空间错误

Question

I have deployed an very big application, and when I tried to start up the server its giving

"Out of memory Error" : PermGen space

Since am using tomcat 5.5, i have no "setenv.bat" inside bin folder. So i have set JAVA_OPTS which is in "catalina.bat". I have given like.

set JAVA_OPTS=-server -Xms512m -Xmx1024m -XX:PermSize=128m -XX:MaxPermSize=512m -XX:NewSize=192m -XX:MaxNewSize=384m -Djava.awt.headless=true -Dhttp.agent=Sakai -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false -Dsun.lang.ClassLoader.allowArraySyntax=true

But still the problem exists. Is there anything i need to specify or need to change in the above snippet so that my server will go up.

Thanks, Jeyaa.

Answer 1

Since you are deploying Sakai, these JAVA_OPTS should be all you need for a small install, as they are what I have used for a number of years:

-server -XX:+UseParallelGC -Xmx1024m -XX:PermSize=512m -XX:MaxPermSize=512m -Djava.awt.headless=true -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false -Dsun.lang.ClassLoader.allowArraySyntax=true -Dhttp.agent=Sakai

Note that what you want for your particular issue is to increase the PermSize settings.

Answer 2

Your best bet, if you're using a Sun JVM, is to download Visual VM 1.3.3 and install all the plugins. It'll let you see threads, memory , etc.

Start Visual VM first, then start Tomcat by selecting its JRE in Visual VM. You'll be able to see what's going on then.

You have a lot of memory there. You must be doing something in your code to make this happen.

Answer 3

我建议您使用Java HotSpot发行版中包含的工具JVisualVM来检查PermGen空间大小并查看GC统计信息

Answer 4

Try doubling the MaxPermSize with -XX:MaxPermSize=1024m . If the problem persists, then also try enabling heap-dumping on OutOfMemoryError with the -XX:+HeapDumpOnOutOfMemoryError flag, and then open the memory dump with Eclipse Memory Analyser to figure out what is taking up all that memory. The memory dumping takes a long time, so be patient. It could be that you have a leak that needs to be plugged. For instance, classes being endlessly generated, or lots of Strings being intern 'ed.

I once had a memory leak because I created Log4J loggers from dynamically generated Strings, and it turned out that Log4J interned all those strings. This meant that our program crashed with OOM in the PermGen space after running for 3 days. Not good.