Thanks for your reply..
But our scenario needs more.We need to filter tasks on time basis like today,last week with respect to user's timezone. As u said, if we set the original timezone(jvm of taskservice), as a task parameter,then we need to query the task content first ,then get the timezone. After that only we can convert to user's timezone. If 'timezone' is a database field then things will be easy(i mean querying). If u can add this provision in your implementation it will be very helpful...