Hi Skumar,
I have very little work related experience with Spring 4.
But I know some
EJB 3 which has similar concept with Spring.
It took me 16 months to study.
If you know bean, AOP, transaction, restful services, JPA,
servlet and web security, that will help you to pass.
I strongly recommend Dominik Cebula's certification courses on Udemy.