Thank you Clebert ) I am already doing exactly this, and this is thread-safe for read-access. Here is the benchmark for my cache implementation: Sun JDK 1.5.0_07 (x64): Without Serialization: 2.3713 usec JBossSmartClone (DataContainer): 44.784 usec JBossSerialization: 68.773 usec JavaSerialization: 167.959 usec Sun JDK 1.6.0_rc (x64): Without Serialization: 2.1233 usec JBossSmartClone (DataContainer): 34.639 usec JBossSerialization: 57.145 usec JavaSerialization: 152.6278 usec (Note that x64 JDK6 doesn't offer much performance gain, unlike x86 one) Amount of garbage generated is HUGE for all 3 copying methods. Approximate proportions are: JBossSmartClone: 300MB JBossSerialization: 800MB JavaSerialization: 1200MB Much of the garbage comes from ArrayList resizing algorithm, THash rehashing, etc. I'll try to patch some code to use Javolution's PoolContexts. Maybe this will help. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3967170#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...