persisting object of perticular date format

[ram <ra...@yahoo.co.in>]

I have a date in string format 
    
 format yyyy-MM-dd'T'HH:mm:ss.
   e.g.2010-12-25T12:00:00

I created entity from the tables . Here is my employee entity.

Class Emp{
  String id,
  java.sql.date joinDate
}

 As i see to_date() is not applicable in JPA,  How can i persist the joined date in the same format 2010-12-25T12:00:00 into the database by using jpa. 

How can i specify this format yyyy-MM-dd'T'HH:mm:ss.

   Later on i want to search the emp who has joined in the format (yyyy-mm-dd) 2010-12-25, so that i can get all the values from the database
2010-12-25T12:00:00
2010-12-25T11:00:00
2010-12-25T10:05:00

@NamedQuery(name="getEmployeeByDate",query="select p from Emp p where p.joinDate =? ")



Thanks,
Ram