Error : class_name is not mapped, Hibernate

You may get this error while using Hibernate with Java. There could be multiple reasons why this can happen

1. You haven't really mapped the class name in config.
2. The class name ( Entity) is case sensitive, meaning you should specify the entity name as is in the query. Your entity name may differ than table  name in DB, but still you will have to refer to exact case of entity name.