Who should use hibernate ?

Hibernate's main role is to reduce sql and jdbc code in the development code, so that developer can easily write business logic.

Also hibernate certainly reduces vendor specific SQL code and help perform database operation using standard Hibernate API. But it should be noted that hibernate does support vendor specific SQL as well.

When should not use hibernate?

Hibernate is not the best solution for data centric applications that only stored procedure in there projects. So to in case of stored procedure, its better to use java middle tier like spring etc. to deal with data obtained and mapped to object, rather than using Hibernate.