GC not releasing memory-Out of Memory Excp.

Question

WL5.1,SP8,JDK1.2.2,Unix.
We have our application running on the above mentioned Env.
We have a memory allocation of 1024MB for the heap. We have three instances of
weblogic server running inside a cluster.
The server calls GC[0] regularly. Once the 100% of the memory is used the server
calls GC[1] and releases memory upto 50% to 60%
appx. But this release of memory keeps reducing and at one point of time it is
not able to release any of its memory.
We tried to get some thread dumps by doing kill -3 and that din't help us much.
we see this kind of behaviour in all the three weblogic instances.
Our application was running quiet a long time and we din't experience any problem
of memory issue before this occured.
Is their anything that I can do to see what objects are their inside the JVM.
I don't have any performance tool installed.
Does weblogic console can give some information on the heap used.
Is their any java utility program that i can use to find the inside's of JVM
Thanks
Krish.

Answer 1

You can find out why 'locale' tag fails by looking at the
ServletException.getRootCause() (in your error jsp page, if
you have one).
Krish <[email protected]\> wrote:
I had the same problem recently and I have some information prior to the server
going out of memory.
Our application uses JSP for presentation.Prior to the server getting out of memory
we faced a problem in one of our JSP being corrupted. The client never got the
full JSP on the screen. We believe that the JSP was corrupted and the server servert
the corrupted file. Then after investigation we used the "touch" command and touched
the file and then it recompiled and the client was able to view the full page.
This problem of serving corrupted JSP code started the same day the out of memery
problem occured. I would like to know that does this corruption leave some thing
in the memory that never got cleaned up by GC[1].
Following is the exception thrown when the client try to acess the JSP.
javax.servlet.ServletException: runtime failure in custom tag 'locale'
     at java.lang.Throwable.fillInStackTrace(Native Method)
     at java.lang.Throwable.fillInStackTrace(Compiled Code)
     at java.lang.Throwable.<init>(Compiled Code)
     at java.lang.Exception.<init>(Compiled Code)
     at javax.servlet.ServletException.<init>(Compiled Code)
The custom tag locale just transalates the string into the local language with
some attibutes passes. Almost all JSP's use this tag. So i don't think there is
a problem in tag.
All in need to know is that if their is some kind of exception in the JSP compilation
will the objects stay in the memory and never get cleaned up.
Thanks in advance
Krish.
"Mike Reiche" <[email protected]> wrote:
JProbe will provide information about java objects in the JVM heap.
Your application was running for a long time, then all of a sudden it
started
running out of memory? Look closely at the last code change you made.
Mike
"Krish" <[email protected]> wrote:
WL5.1,SP8,JDK1.2.2,Unix.
We have our application running on the above mentioned Env.
We have a memory allocation of 1024MB for the heap. We have three instances
of
weblogic server running inside a cluster.
The server calls GC[0] regularly. Once the 100% of the memory is used
the server
calls GC[1] and releases memory upto 50% to 60%
appx. But this release of memory keeps reducing and at one point oftime
it is
not able to release any of its memory.
We tried to get some thread dumps by doing kill -3 and that din't help
us much.
we see this kind of behaviour in all the three weblogic instances.
Our application was running quiet a long time and we din't experience
any problem
of memory issue before this occured.
Is their anything that I can do to see what objects are their inside
the JVM.
I don't have any performance tool installed.
Does weblogic console can give some information on the heap used.
Is their any java utility program that i can use to find the inside's
of JVM
Thanks
Krish.
Dimitri