To improve my system performance I am planning to use distributed computing (using java).
I found several interesting distributed/grid java based frameworks to share CPU.
Can anyone suggest me a good framework to share memory?
I have directly used both gigaspaces and gemstone. I have also used coherence, but not directly. All seems fine -- not sure how to say one is better than another.
The later two are owned by big companies (EMC/VmWare/SpringSource and Oracle respectively) and the first may be shopping for a owner (opinion) -- so support, profession services, etc. may also be available.
Recently, there was a lot of buzz about Red Hat's JSR for Distributed Hash Table, called Infinispan. You can read more about it here While I'm not sure whether it's going to be approved, and it's too early to talk about Java EE 7, it gives us optimistic thoughts that someday DHT in Java might become an open standard...
You might also take a look at CloudTran... gives you persistence from GigaSpaces and Coherence back to distributed databases. Full ACID transactions across the data grid and to the database as well. DISCLAIMER: I work for CloudTran.