Hibernate: Interview Questions and Answers

  1. What is Hibernate?

Hibernate is an open-source Object-Relational Mapping (ORM) framework that simplifies database operations in Java applications.

  1. What are the benefits of using Hibernate?

Hibernate eliminates the need for boilerplate JDBC code, improves performance, supports caching, and provides a consistent object model.

  1. What are the different types of mappings in Hibernate?

Hibernate supports three types of mappings: one-to-one, one-to-many, and many-to-many.

  1. What is the difference between Hibernate and JDBC?

Hibernate is a high-level ORM framework that abstracts away database-specific details, while JDBC is a low-level API for executing SQL statements.

  1. What is an Entity in Hibernate?

An Entity in Hibernate represents a persistent object, which is stored in a database and can be retrieved and modified later.

  1. What is a SessionFactory in Hibernate?

A SessionFactory in Hibernate is a thread-safe factory for creating Hibernate Sessions, which are used to interact with the database.

  1. What is a Hibernate configuration file?

A Hibernate configuration file contains information about the database connection, mapping files, and other Hibernate settings.

  1. What is lazy loading in Hibernate?

Lazy loading in Hibernate delays the loading of associated objects until they are actually needed, improving performance and reducing memory usage.

  1. What is the purpose of a Hibernate Session?

A Hibernate Session is used to perform database operations such as inserting, updating, and deleting objects, and querying the database.

  1. What is a Criteria API in Hibernate?

The Criteria API in Hibernate provides a type-safe and object-oriented way to construct SQL queries dynamically.

  1. What is a Hibernate Transaction?

A Hibernate Transaction represents a single atomic unit of work with the database, which must be completed successfully or rolled back if an error occurs.

  1. What is the purpose of Hibernate caching?

Hibernate caching reduces the number of database queries by storing frequently accessed data in memory, improving performance and scalability.

  1. What is a Hibernate Query Language (HQL)?

Hibernate Query Language (HQL) is a high-level object-oriented query language that allows developers to write database queries using object-oriented syntax.

  1. What is a Second-Level Cache in Hibernate?

A Second-Level Cache in Hibernate is a cache shared across all Sessions in an application, which can improve performance by reducing the number of database queries.

  1. What is a Hibernate Validator?

Hibernate Validator is a framework that provides a set of annotations and classes for validating objects, ensuring that they meet specific constraints.

  1. What is a Proxy object in Hibernate?

A Proxy object in Hibernate is a lightweight placeholder for an Entity, which is loaded from the database only when its properties are accessed.

  1. What is a Hibernate interceptor?

A Hibernate interceptor is an object that can intercept and modify SQL statements generated by Hibernate, allowing developers to customize Hibernate behavior.

  1. What is the difference between Hibernate and JPA?

JPA is a Java specification for ORM frameworks, while Hibernate is a popular implementation of that specification.

  1. What are the different ways of mapping Inheritance in Hibernate?

Hibernate supports three ways of mapping Inheritance: Single Table, Joined Table, and Table Per Class.

  1. What is the difference between FetchType.LAZY and FetchType.EAGER?

FetchType.LAZY loads associated objects only when they are actually needed, while FetchType.EAGER loads them immediately along with the parent object.


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