OOME: Java heap space

WebLogic 10.3.3

Sun hotspot JDK 1.6

Sun Solaris 10 Zones 

RedHat Linux 2.6 on  Processor x86_64

Error Stack 

java.lang.OutOfMemoryError: Java heap space.

java.lang.OutOfMemoryError: Java heap space

at weblogic.utils.io.Chunk.<init>(Chunk.java:293)

at weblogic.utils.io.Chunk.getChunk(Chunk.java:141)

at weblogic.utils.io.ChunkedOutputStream.advance(ChunkedOutputStream.java:52)

at weblogic.utils.io.ChunkedOutputStream.write(ChunkedOutputStream.java:65)

at java.io.ObjectOutputStream$BlockDataOutputStream.drain(ObjectOutputStream.java:1838)

Analysis Questions

1. What has changed before you saw the first OOM in your10.3.3 environment? 

Nothing has changed in the environment 

2. Did load increased for instance? Did the number of users increased?

No, the number of users are same as previous.

3. How frequently are you seeing the OOM error? In other words, how long does it take for the OOM to happen after you start the server?

In the same physical location it is happening weekly.

Why it happens only Web-Tier?

What MAT says? weblogic.utils.io.Chunk

How do I eliminate this?

This is the big matter for me, it was bothering me since few days.