* It is used to define specific mappings from Java classes to database tables.
* It is used to define the mapping of unique ID attribute in class to the primary key of the database table.
* It is used to generate the primary key values automatically.
* It is used to map a Java class property to a column in the database table.
* It is used to map a java.util.set, java.util.Sortedset property in hibernate.
* It is used to map a java.util.List property in hibernate.
* It is used to map a java.util.Collection property in hibernate.
* It is used to map a java.util.Map property in hibernate.
