Hi
I followed up the discussion for Out of memory error, but could not find something
helpful to me. I am also running into Out Of Memory error in tomcat. I would
apprecaite if anybody would like any insights on this one.
My scenario is as follows :
1. I have multiple servlet threads corresponding multiple http requests (I send
simultaneous requests through req. generator),
2. Each servlet thread does some processing, generates an async. event and waits to
receive response event from backend event generator.
3. Each servlet session is supposed to wait for a separate event. I have a (had to
have) a single static hashmap of objects where I put a lock object and ID of the
message sent. The servlet thread waits on that lock object.
4. When any event is generated the backend thread accesses proper object through the
use of message ID from hashmap and notifies appropriate servlet thread which in turn
returns the response back to the user.
If I have more than certain number of requests simultaneously, I get OutOfMemory
error, But if I add little delay in those incoming requests I never encounter any
problem. I am using an object pool to pre-create 1000 objects which I letter reuse for
locking. The problem exists only in the wait call, that too in servlet. My test
program with the same wait/notify and multiple threads work file, too.
I could not use profiler, somehow JProbe crashed on Solaris, and I couldn't get any
help on that. I have increased the JVM memory, but to no effect.
This is my actual code :
public
String send(String aMessage, String aSubject, String aMsgId) throws Exception
{
try
{
Object lLock = getLockFromMap(aMsgId);
sendMessage(aSubject, aMessage);
// main thread will wait on every message
// till gets notified by the receiver thread
synchronized(lLock)
{
lLock.wait(mWaitTimeout);
}
}
catch( Exception e )
{
e.printStackTrace();
throw e;
}
catch( InterruptedException e)
{
System.exit(0);
}
MessageInfo mInfo = removeMessageInfoFromMap(aMsgId);
String msgData = new String(mInfo.getMsgData());
mObjPool.release(mInfo);
mInfo = null;
return msgData;
}
The methods to access map are synchronized.
Thanks
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