Hibernate is one of the most widely used ORM frameworks for Java. If you're preparing for a software engineering interview that requires knowledge in Hibernate for Java, it's a good idea to practice some commonly asked interview questions.
As you may already know, Hibernate is used in Java to access the data layer. However, this framework alone is not enough; it must be supported by two other frameworks — Spring and Struts. So, it is essential to draw references between these frameworks while answering interview questions on Hibernate in Java.
Whether you are a fresher or experienced software developer looking for sample interview questions and answers on Hibernate in Java, we’ve got you covered!
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We will cover the following topics in this article:
- Interview Questions and Answers on Hibernate in Java for Beginners
- Interview Questions and Answers on Hibernate in Java for Intermediate Developers
- Interview Questions and Answers on Hibernate in Java for Experienced Developers
- Tips to Prepare for Your Next Tech Interview
- FAQs on Interview Questions and Answers on Hibernate in Java
Interview Questions and Answers on Hibernate in Java for Beginners
Beginners and freshers can go through these commonly asked Hibernate in Java interview questions:
1. Define Hibernate along with its advantages.
Hibernate is a Java framework that helps a Java application interact with the database. It is an object-relational mapping (ORM) tool, which allows a developer to map POJO.
Its advantages are:
- It is open-sourced and lightweight
- Fast performance
- Helps in generating independent database queries
- Creates an automatic table
- Provides query statistics and database status
2. What is an ORM tool?
ORM tool is a technique that maps the object stored in the database by using Java API to interact. This process helps simplify data creation, manipulation, and access.
3. Why is Hibernate Framework used?
Hibernate is better than other technologies like JDBC:
- Unlike JDBC, Hibernate is database software independent
- Handles code portability
- Strengthens object-level relationship
- Helps in reducing the length of code with increased readability
- Provides built-in features for versioning, time stamping, caching, lazy loading, etc.
4. What are the important interfaces of Hibernate framework?
Hibernate core interfaces are:
5. What is a Session?
A session is an object that helps maintain the connection between Java object application and database.
Additional Hibernate Java Interview Questions for Beginners:
- Can you share a session between threads?
- What is Hibernate SessionFactory?
- What are the other functionalities supported by Hibernate?
- List the collection types in Hibernate.
- What are the advantages of Hibernate over JDBC?
- Define lazy loading.
- Differentiate between first-level and second-level cache.
- Explain the concept of Hibernate inheritance mapping.
- Describe Hibernate configuration file.
- Can SQL injection attack Hibernate?
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Interview Questions and Answers on Hibernate in Java for Intermediate Developers
Here are a few moderate-level interview questions and answers on Hibernate in Java:
1. Explain Hibernate mapping file.
This is an XML file used to define the entity bean fields and corresponding database column mapping. When a project uses third-party classes, where JPA annotations are provided by hibernating cannot be used, Hibernate mapping files comes in handy.
2. Mention some of the annotations used for Hibernate mapping
Hibernate supports JPA annotations. Some of which are as follows:
3. What are the collection types in Hibernate?
There are five types of collection in Hibernate:
4. Define Hibernate architecture.
The Hibernate architecture consists of many objects, like session, session factory, query, etc. And the applications developed using Hibernate are mainly categorized into four parts:
- Java Application
- Hibernate framework configuration and mapping files
- Internal API: JDBC, JTA, JNDI
- Database: MySQL, PostgreSQL, Oracle, etc.
5. What is the criteria API in Hibernate?
Criteria API in Hibernate helps developers build dynamic criteria queries on the persistence database. This is a powerful and more flexible HQL query. It allows to programmatically development criteria objects.
Additional Interview Questions on Hibernate in Java
- Define HQL.
- How can one-to-many associations be used in Hibernate?
- Differentiate between openSession and getCurrentSession?
- What is the difference in get() and load() in Hibernate session?
- Differentiate between save() and saveOrUpdate() method in Hibernate session.
- What are many-to-many associations?
- What is the importance of the session.lock() method?
- Define Hibernate caching.
- What are the types of Hibernate caching?
- When must you use merge() and update() in Hibernate?
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Interview Questions and Answers on Hibernate in Java for Experienced Developers
Experienced Java professionals must prepare for the following types of interview questions and answers on Hibernate in java:
1. What is Hibernate tuning?
The process of optimizing the performance of Hibernate applications is termed Hibernate tuning. Performance tuning strategies include:
- SQL Optimization
- Session Management
- Data Caching
2. How to integrate Hibernate with Struts2 or Servlet web applications?
- First, you register a custom “ServletContextListener."
- Then, initialize the Hibernate session store it in the servlet context.
- Action class helps get the Hibernate session from the servlet context and perform the hibernate task.
3. What are the three states of a persistent entity?
The three states are, Transient, Persistent, and Detached.
- Transient: No association with the session and also has no representation in the database.
- Persistent: Associating with a session will make a transient session persistent.
- Detached: On closing the session, the persistent instance becomes a detached instance.
4. Can we call entity class final?
Entity class cannot be declared final because Hibernate uses proxy classes and objects for lazy data loading. This is achieved by extending the entity bean. Therefore, if the entity bean is made final, it won't extend.
5. Explain query cache.
The hibernate framework provides an optional feature called cache region for queries' resultset. Query cache is useful for frequent queries and within the same parameters.
Additional Interview Questions on Hibernate in Java for Experienced Developers
- Explain N+1 SELECT problem in Hibernate.
- How will you solve the N+1 SELECT problem in Hibernate?
- What are concurrency strategies?
- Define Single Table strategy.
- Explain Table per Class strategy.
- Describe Named SQL Query.
- What are some of the benefits of NamedQuery?
- How does transaction management work?
- What is the process of creating a primary key using Hibernate?
- How to check Hibernate generated SQL on console?
Beginners can also prepare for these interview questions on Hibernate in Java to make a good impression.
Recommended Reading: Top Java String Interview Questions You Need to Practice
FAQs on Interview Questions and Answers on Hibernate in Java
Q1. Is session thread-safe in Hibernate?
No, the session is not thread-safe, as many threads can access the same simultaneously.
Q2. What is the core interface of Hibernate?
- Session interface
- SessionFactory interface
- Configuration interface
Q3. How many types of cache are there in Hibernate?
There are mainly two levels of cache, first-level and second-level.
Q4. Why is Hibernate used in Java?
Hibernate is an ORM (Object Relational Mapping) tool for Java. It reduces the lines of code by sustaining the object-table mapping.
Q5. What is ORM?
ORM (Object Relational Mapping) is a mapping tool pattern. It primarily converts the data in a relational database into an object for object-oriented programming. It helps simplify data retrieval, creation, and manipulation.
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