Hibernate Interview Questions and Answers
Ques 16. What is HQL?
Ans. HQL stands for Hibernate Query Language. Hibernate allows the user to express queries in its own portable SQL extension and this is called as HQL. It also allows the user to express in native SQL.
Ques 17. What are the most common methods of Hibernate configuration?Ans. The most common methods of Hibernate configuration are:
* Programmatic configuration
* XML configuration (hibernate.cfg.xml)
Ques 18. What are the important tags of hibernate.cfg.xml?Ans. An Action Class is an adapter between the contents of an incoming HTTP request and the corresponding business logic that should be executed to process this request.
Ques 19. What role does the Session interface play in Hibernate?Ans. The Session interface is the primary interface used by Hibernate applications. It is a single-threaded, short-lived object representing a conversation between the application and the persistent store. It allows you to create query objects to retrieve persistent objects.
Session session = sessionFactory.openSession();
Session interface role:
* Wraps a JDBC connection
* Factory for Transaction
* Holds a mandatory (first-level) cache of persistent objects, used when navigating the object graph or looking up objects by identifier
Ques 20. What role does the SessionFactory interface play in Hibernate?Ans. The application obtains Session instances from a SessionFactory. There is typically a single SessionFactory for the whole application created during application initialization. The SessionFactory caches generate SQL statements and other mapping metadata that Hibernate uses at runtime. It also holds cached data that has been read in one unit of work and may be reused in a future unit of work.
SessionFactory sessionFactory = configuration.buildSessionFactory();
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