Hibernate Disadvantages

Since hibernate generates lots of SQL statements at runtime so it is slower than pure JDBC.
Hibernate is not much flexible in case of composite mapping. This is not disadvantage since understanding of composite mapping is complex.
Hibernate does not support some type of queries which are supported by JDBC
Boilerplate code issue, actually we need to write same code in several files in the same application, but spring eliminated this.
Not good for small project. (Small project will have less number of tables , introducing entire Hibernate framework will be overhead than useful)