"Now there is a feasibility where in Candidates, join  the service and then take leave to pursue higher studies. They can come back and join the position once they complete the course."

Can anybody enlighten with document/document how it is feasible,  please help.

If you attend an interview this year, they expect you to join this y ear itself. They will not hold the position for the next 2-3 years until you complete your PG. The position has been opened for a vacancy to be filled now. It cannot hold for the next 2-3 years. If you want to complete your PG and come back, you will have to reapply and then based on the position available, you get a designation. Now there is a feasibility where in Candidates, join  the service and then take leave to pursue higher studies. They can come back and join the position once they complete the course.