Hibernate interview questions are commonly asked in technical interviews at top companies, especially in Java interviews. Hibernate is a widely popular Object-Relational Mapping tool that provides a framework to map domain models to relational databases in Java. The tool offers high-level functions to handle objects and is free-to-use software used extensively by developers who code applications and software in Java.
You may have to attempt Hibernate interview questions if you choose Java as your programming language. As such, you don’t necessarily have to know Hibernate in-depth to answer basic Hibernate interview questions. But, knowing your way around the tool is extremely useful to make a good impression, especially if you’re a Java programmer.
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In this article, we’ll look at some of the most frequently asked Hibernate interview questions and answers at tech interviews of top companies like Facebook, Google, Amazon, and Microsoft, among others.
Here’s what we’ll cover in this article:
- Popular Hibernate Interview Questions and Answers
- FAQs on Hibernate Interview Questions
Popular Hibernate Interview Questions and Answers
Let’s look at some of the most popular Hibernate interview questions and answers asked at tech interviews. We’ve compiled a list of questions asked to freshers and experienced developers.
Q1. Explain the ORM Feature in Hibernate
ORM in Hibernate stands for Object Relational-Mapping and is a fundamental feature in Hibernate that converts data contained in a relational database to Object-Oriented constructs. Hibernate makes it extremely easy to perform functions like data retrieval, data manipulation, and data storage.
Q2. List out some of the important interfaces that are part of Hibernate
The interfaces that are part of the Hibernate Framework are:
Q3. What do you understand about a Session in Hibernate?
Sessions are objects that keep the connection between the database and the application. Sessions use many methods to perform various functions such as data retrieval, storage, modification, and deletion. Sessions also specifically contain Factory Methods to return Transaction, Query, and Criteria Objects.
Q4. What do you understand by Lazy Loading in Hibernate?
This is one of the most common Hibernate interview questions that is asked in coding interviews. Lazy Loading is a default feature in Hibernate that is used to load child objects into the database. Lazy Loading improves the performance of applications that use Hibernate and are coded in Java.
Q5. What do you understand by the Hibernate Configuration file?
The Hibernate configuration file contains session and database-related configurations that are to be used in the application. The file, hibernate.cfg.xml, is located in the folder - src/main/resource.
Q6. In Hibernate, explain the process of creating an immutable task
In Hibernate, a task can be made Immutable by giving it the value - markingmutable=false. IN the case of annotations, an immutable task can be created through - @Immutable annotation.
Q7. What type of information does the Hibernate Configuration file define?
The configuration file in Hibernate is used to define:
The URL, Username, Driver Class, and Password
Properties including show_sql, dialects, and second_level_cache
Q8. What are the different Inheritance Mapping Strategies that are available in Hibernate?
This is a common Hibernate Interview Question that is asked in tech interviews. The different Inheritance Mapping Strategies that are available in Hibernate include:
- Single Table Strategy
- Joined Table Strategy
- Mapped Super-Class Strategy
- Table-Per Class Strategy
Q9. Does Hibernate offer immunity against SQL injection?
This is another popular Hibernate interview question often featured at technical interviews, especially in SQL developer interviews at FAANG+ companies.
An SQL Injection Attack is a severe threat that allows hackers to view sensitive data in a database by interfering with queries sent by an application to the database. Hibernate, unfortunately, does not provide immunity against SQL Injection attacks.
Q10. What are some practices that developers can follow to avoid SQL Injection attacks?
Some constructive practices that developers can follow to avoid SQL Injection attacks include:
- Making use of pre-prepared statements that employ parameterized queries
- Performing Input sanitation
- Using stored procedures
Q11. Name some technologies that Hibernate supports.
Some technologies that Hibernate supports include:
- XDoclet Spring
- Eclipse Plugins
Q12. How do you carry out the process of association mapping in Hibernate?
This is an important Hibernate interview question that features in technical interviews. Association mapping in Hibernate can be carried out by:
- One-to-One association
- Many-to-many association
- One-to-many association
Q13. What is HQL in the context of Hibernate?
HQL stands for Hibernate Query language. It is an Object-Oriented Query Language that is independent of the database in question.
Q14. What do you understand about SessionFactory in Hibernate?
SessionFactory in Hibernate is fundamentally an object of the factory class that helps retrieve session objects in the Hibernate framework. SessionFactory is created when running the application and is usually saved from being used for later. All threads of a particular application generally use SessionFactory.
Q15. Explain the difference between opensession() and getcurrentsession()
Both getcurrentsession() and opensession() are methods in Hibernate that help to navigate sessions. The getcurrentsession() function returns the current session while the opensession() helps create or start a new session. Both of these can be configured in the Hibernate configuration file.
Q16. What is the difference between get() and load() methods in Hibernate?
The two methods are fundamentally used to deal with objects in Hibernate. The get() method will return a null value if a particular object in question isn’t found, while the load() method will throw an exception if the given object isn’t located in the class.
Q17. What do you understand about the (N+1) Select problem in Hibernate?
The (N+1) Select problem is a result of lazy loading, a key feature in Hibernate. Hibernate executes N+1 queries - 1 query for all the items in question when the query executes an entire batch of items and n queries for each item.
Q18. How would you solve the N+1 select problem in Hibernate? What are some strategies that can be used?
The (N+1) select problem in Hibernate can be solved by:
- Disabling Lazy Loading
- Employing a Subselect Fetching Strategy
- Carrying out pre-fetching in batches
Q19. What is the difference between persist() and save() in Hibernate?
The difference between the two methods is that while the persist() method has a void return type and doesn’t return anything, the save() method returns a serializable object when used.
Q20. Which are the different collection types in Hibernate?
This is another important Hibernate interview question that is asked in technical interviews. The different collection types in Hibernate are:
These collection types are predominantly used for One-to-Many relationship mappings in Hibernate.
Q21. List out some benefits of using the Hibernate template class?
The benefits of using the Hibernate template class include:
- Automation of exception handling in Hibernate - a key feature
- Interactions between sessions are seamless and simplified
- Automation of session closing
Q22. What are some design patterns that are part of the Hibernate framework?
The design patterns in the Hibernate framework are:
- Data Mapper
- Proxy Pattern
- Factor Pattern
- Domain-model Pattern
Q23. What do you understand about Data Mapper in Hibernate?
Data Mapper is a design pattern in Hibernate that helps move and allow data to interact between the database and the object while also maintaining the independence of the entities.
Q24. What do you understand about the Proxy Pattern in Hibernate?
A Proxy Pattern is a design pattern in Hibernate. The primary function of Proxy Pattern is to assist the process of Lazy Loading in Hibernate.
Q25. What is the Domain-model Pattern in Hibernate?
The Domain-model pattern is an object model in the given domain that includes elements of both data and behavior.
Q26. What do you understand about the Dirty Checking feature in Hibernate?
This is yet another Hibernate interview question that comes up frequently in tech interviews. The Dirty Checking feature is an important feature in Hibernate that allows developers to save time by automatically updating fields that need to be changed and leaving the other fields untouched, thereby saving developers from “write” actions that can sometimes be time-consuming.
Q27. How does an Object in Java become a Hibernate object?
The means to do this is to provide a no argument, default constructor. That way, a Java Object becomes part of the Hibernate entity.
Q28. What is Hibernate tuning?
Hibernate tuning is a process by which the performance of a Hibernate application is enhanced. The different Hibernate Tuning strategies include:
- Session Management
- SQL optimization
- Data Caching
Q29. What is Named SQL Query in Hibernate?
Named SQL Query is a feature in Hibernate that is used to define and store queries at a central location, to be used easily while running an application.
Q30. What are the different states of persistent entities in Hibernate?
The different states of persistent entities in Hibernate include:
- Detached - In this state, if you close a session, the persistent instance becomes a detached instance.
- Transient - Transient entities do not have database representation and aren’t part of the Hibernate session.
- Persistent - A persistent entity is directly associated with the Hibernate session in question.
The above Hibernate interview questions and answers will help you prepare for technical interviews at top companies. If you want to practice some coding problems for your upcoming technical interview, visit our Problems Page.
FAQs on Hibernate Interview Questions
Q1. What is Hibernate mainly used for?
Hibernate is mainly used to map Object-oriented domain models to relational databases and is predominantly used as a tool for the Java programming language. Hibernate makes it easy for developers to design complex code and software in java for various applications and systems.
Q2. What are the important topics around which Hibernate Interview Questions are asked in technical interviews?
Some important topics include Lazy Loading, Hibernate Configuration Files, SQL injection risks associated with Hibernate, annotations available with Hibernate, characteristics of Hibernate architecture, and APIs in Hibernate.
Q3. Are you asked to write program code during Hibernate interviews?
Yes, you can be asked to elucidate a particular feature in Hibernate through code. You will be asked to write code and answer related Hibernate Interview Questions mostly during On-site interviews at companies.
Q4. Are Hibernate Interview Questions mainly asked in Java interviews?
As Hibernate is a programming ORM tool in Java, you can expect to Hibernate interview questions only in Java and SQL developer interviews.
Q5. What are the different types of caching available in Hibernate?
Hibernate has three types of caching solutions - first-level cache, second-level cache, and query cache. The first-level cache in Hibernate happens at the Session level, while the second-level cache happens at the SessionFactory level.
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