This question may sound too simple ..Anyways I have read Hibernate provides dirty checking. But how do I implement it. In the reference guide different optimistic locking strategies are mentioned like all, dirty , none , version . Can I specify this on primtive types ? Also, it again involves some performance issues, So can anyone throw light on whether this is the way to specify dirty checking..? If not, then pls let me know how to do it

Hibernate allways does dirty checking. What is your exact problem? You don't need to implement anything yourself.

Oh Okey. So by default hibernate always does dirty checking. Can I disable /enable on selected fields/objects? Also, what strategy it follows for dirty checking? Any links on this..

I really don't get what your problem is. What do you mean by "dirty checking strategy"? If you modify your object inside session scope, it is detected dirty and the changes get persisted, simple as that.