Much like Spring, Hibernate changed the software development landscape when it first appeared on the scene. The timing was ideal. Developers were frustrated by the complexity of J2EE and the overhead associated with using EJB for persistence in particular. Hibernate solves the persistence problem through simplicity and clean, thoughtful design.
Also like Spring, Hibernate relies heavily on POJOs. Other ORM frameworks force developers to muddy their domain model with restrictive and rigid requirements, ...