Describe the important interfaces of Hibernate framework?

Important interfaces of Hibernate framework are:

• SessionFactory (org.hibernate.SessionFactory)
  It is an immutable thread safe cache of compiled mappings for a single database.
  We are supposed to initialize SessionFactory once and then we are allowed to cache and reuse it.
  The SessionFactory instance is used to return the session objects for database operations.
• Session (org.hibernate.Session)
  It is a single threaded and short-lived object, which represents a conversation between the persistent store and the application.
  The session should be opened only when it is required and should be closed as soon as the user is done.
  The session object is the interface between hibernate framework and Java application code and it provides methods for the CRUD operations.
• Transaction (org.hibernate.transaction)
  It is a single threaded and short-lived object used by the application, which specifies atomic units of work.
  The application is abstracted from the underlying JDBC or JTA transaction.