This is due to less Internet bandwidth of ISP. Increase the Internet bandwidth to avoid this problem. If Internet bandwidth goes down all the request gets qued up and eat all the virtual memory of the server.
Um, are you sure you have enough information to provide an answer? The original post said nothing about ISPs or bandwith, and he would be seeing java.lang.OutOfMemory errors if he had a memory problem.
We have fixed the problem !!
It has nothing to do with bandwidth, there is no ISP involved as this is an internal company system.
The problem was that we had the wrong version of the Oracle OCI driver loaded. Once the correct version was installed the problem resolved itself.
The reason why the performance was so bad against the cluster would appear to be linked to one of the patches in the OCI Oracle drivers