Top Hibernate Interview Questions and Answers (2024)

In this article we have gathered the latest and most asked Hibernate Interview Questions and Answers for both freshers and 2/3/5/10 years experience candidates. These Hibernate Interview Questions will get you familiar with the types of questions that you will likely come across during your interview.

Hibernate is a popular open-source object-relational mapping (ORM) tool for the Java programming language. It is used to map Java objects to relational database tables, and vice versa. This allows developers to work with the Java objects and their properties, rather than having to write SQL queries to interact with the database directly.

If you’re a Java developer, you may be asked about Hibernate in a job interview. In this post, we’ll cover some common Hibernate interview questions and answers to help you prepare.

So let’s get started :

1. What is Hibernate?

Hibernate is a popular open-source object-relational mapping (ORM) tool for the Java programming language. It is used to map Java objects to relational database tables, and vice versa.

2. What is ORM?

ORM (Object Relational Mapping) is the fundamental concept of Hibernate framework which maps database tables with Java objects and then provides various APIs to perform various types of operations on the data tables.

3. What are some advantages of using Hibernate?

There are several advantages to using Hibernate, including:

Improved developer productivity: Hibernate eliminates the need to write SQL queries, which can be time-consuming and error-prone. This allows developers to focus on the business logic of their applications, rather than having to worry about the details of interacting with the database.
Improved performance: Hibernate generates optimized SQL queries, which can improve the performance of applications. It also provides caching mechanisms, which can further improve performance by reducing the number of database queries that need to be executed.
Improved portability: Hibernate is designed to be database-agnostic, meaning that it can work with any database that has a JDBC driver. This allows developers to easily switch between different databases, or to use different databases for different parts of the same application.
Improved maintainability: Hibernate makes it easy to update and evolve the database schema, without having to manually update the SQL queries in the application code. This can make it easier to maintain and evolve an application over time.

4. What are the core interfaces of Hibernate?

The core interfaces of Hibernate framework are:

Configuration
SessionFactory
Session
Query
Criteria
Transaction

5. Define criteria in terms of Hibernate.

The objects of criteria are used for the creation and execution of the object-oriented criteria queries.

6. What’s the usage of Configuration Interface in hibernate?

The configuration interface of the Hibernate Framework is used to configure Hibernate. It is also used to hibernate bootstrap. Hibernate’s mapping documents are located using this interface.

7. What are POJOs and what’s their significance?

POJOs (Plain Old Java Objects) are Java beans with appropriate getter and setter methods for each property.
Using POJOs instead of simple Java classes results in an efficient and well-formed code.

8. How is SQL query created in Hibernate?

The SQL query is created with the help of the following syntax:

Session.createSQLQuery

9. What does HQL stand for?

Hibernate Query Language

10. What is criteria API?

Criteria is a simple yet powerful API of hibernate which is used to retrieve entities through criteria object composition.

11. What is the Object-Relational Impedance Mismatch, and how does Hibernate address it?

The Object-Relational Impedance Mismatch is a term used to describe the differences between the way data is represented in object-oriented programming languages, such as Java, and the way it is represented in relational databases. Hibernate addresses this by providing a layer of abstraction between the Java objects and the database.

12. What is a Hibernate Session, and how is it used?

A Hibernate Session is a short-lived object that represents a single unit of work with the database. It is used to create, read, update, and delete persistent objects, and to control the transaction boundaries. A Hibernate Session is created by a SessionFactory, which is a thread-safe object that is created once and used throughout the life of an application.

13. What is a Hibernate Criteria Query, and how is it used?

A Hibernate Criteria Query is a type of query that is created using the Criteria API. It allows developers to programmatically create and execute queries, without having to write SQL. This can make it easier to write dynamic and flexible queries, and to avoid the pitfalls of using string-based queries, such as SQL injection attacks. A Hibernate Criteria Query is created by first creating a Criteria object, which is associated with a specific entity class. The query is then built using the various methods provided by the Criteria object, and finally executed by calling the uniqueResult() or list() method.

14. What is a Hibernate Transaction, and how is it used?

A Hibernate Transaction is a unit of work that is performed on the database. It is used to group together multiple operations, such as creating, updating, and deleting persistent objects, and to ensure that these operations are either all completed, or all rolled back, in case of an error. A Hibernate Transaction is created by calling the beginTransaction() method on a Hibernate Session, and then committed or rolled back using the commit() or rollback() methods.

15. What is a Hibernate Query Language (HQL) query, and how is it used?

A Hibernate Query Language (HQL) query is a type of query that is written in a SQL-like syntax, but operates on objects and properties of persistent classes, rather than on tables and columns of a relational database. It allows developers to write queries that are portable across different databases, and that are easier to write and maintain than SQL queries. A Hibernate Query Language query is created by calling the createQuery() method on a Hibernate Session, and then setting the query string and any necessary parameters. The query is then executed by calling the uniqueResult() or list() method.

16. What is a Hibernate Native SQL query, and how is it used?

A Hibernate Native SQL query is a type of query that is written in SQL, using the syntax and features of the underlying database. It allows developers to take advantage of the specific features of a particular database, or to use SQL constructs that are not supported by HQL. A Hibernate Native SQL query is created by calling the createSQLQuery() method on a Hibernate Session, and then setting the query string and any necessary parameters. The query is then executed by calling the uniqueResult() or list() method.

17. What is a Hibernate association, and how is it used?

A Hibernate association is a relationship between two persistent classes, such as one-to-one, one-to-many, many-to-one, or many-to-many. It is used to represent the relationships between objects in the application, and to manage the corresponding foreign keys in the database. Hibernate associations are typically defined using annotations or XML mapping files, and are then automatically managed by Hibernate when the objects are persisted to or loaded from the database.

18. What is a Hibernate Interceptor, and how is it used?

A Hibernate Interceptor is a callback mechanism that allows developers to intercept the various events that occur during the life cycle of a persistent object, such as when it is loaded, saved, updated, or deleted. This can be used to perform custom tasks, such as auditing, or to enforce custom constraints on the data. A Hibernate Interceptor is implemented by creating a class that extends the EmptyInterceptor class, and then overriding the methods that correspond to the desired events. The interceptor is then registered with Hibernate by calling the setInterceptor() method on the SessionFactory.

19. What is a Hibernate Criteria Restriction, and how is it used?

A Hibernate Criteria Restriction is a condition that is used to filter the results of a Criteria Query. It can be used to specify conditions on the properties of the persistent class, such as equality, inequality, nullness, or membership in a particular set of values. A Hibernate Criteria Restriction is created by calling the appropriate methods on the Criteria object, such as eq(), ne(), isNull(), or in(). The restrictions are then combined using logical operators, such as and() or or(), and applied to the query by calling the add() method.

20. What is a Hibernate Persistent Class, and how is it used?

A Hibernate Persistent Class is a Java class that is mapped to a relational database table, and that is managed by Hibernate. It typically has a no-arg constructor, and getter and setter methods for each persistent property. A Hibernate Persistent Class is annotated with the @Entity annotation, and its properties are mapped to columns in the database table using the @Column annotation. The mapping is then defined in a hibernate.cfg.xml file, or in a separate mapping file. The persistent class is then used to create, read, update, and delete objects in the database.

The Hibernate Interview Questions and Answers covered in this post should help you prepare for such an interview and improve your understanding of Hibernate. We hope these Hibernate Interview Questions help you in cracking your next job Interview easily.

All The Best!

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