OutOfMemoryError in openfire 3.8.2 due to thousand's instance of org.apache.mina.filter.executor.ExecutorFilter$SessionBuffer

We recently moved our openfire server (3.8.2) from one host to other and we started facing OOME issue's in it. Please find below heap dump snapshot of it -

On old host (same configuration as new host in terms of CPU, memory etc), openfire server works perfectly fine for almost a year without a bounce with 700 concurrent sessions.

We are using 64 bit Linux box having 8 GB of RAM and Java 1.6 and PostgreSQL database

In our system, all users send messages to single user/listener periodically using XMPP (1 min or so).

Any help on this is highly appreciated.

Thanks,

Keshav