Ganesh Pulihi,
can any one please let me know the process of unit testing of controller , service and persistence layer classes in liferay in detail
See
this related recent post (by yourself, actually).
On top of that: generated classes (like persistence) won't need tests - either the generator (service builder) works, or it doesn't. If you add custom code: Extract the logic, and test those extracted portions, as outlined in the linked post.
