Top 40 Spring Interview Questions (With Example Answers)

Updated 17 October 2022

The Spring framework is an open-source technology for developing Java products and applications. Web and application developers are often quizzed on this technology during job interviews. Learning how to demonstrate your expertise in the Spring framework can help you secure employment. In this article, we list some frequently asked Spring interview questions and provide few sample answers to help you do well during your next interview.

12 Important Spring Interview Questions And Answers

If you are preparing for an upcoming interview, review these spring interview questions:

1. What is the Spring framework?

Spring is one of the most widely-used technologies by web developers. A hiring manager is looking to understand your knowledge of the framework and familiarity with its key features.

Example: "The Spring framework is an open-source and lightweight technology used to develop Java web applications. Spring simplifies the web application development process by providing several helpful extensions and supporting other popular technologies, like JSF, Hibernate and Structs. This helps improve essential features like security and database connections. For this reason, it is also called the 'framework of frameworks.' The layered architecture of Spring helps develop large and complex Java applications easily."

2. What are the benefits of Spring?

Spring has several benefits for developers and it is important that are able to explain how you have used its features to improve results. You may discuss that it is easy to learn, open-source, cost-effective, loosely coupled and lightweight.

Example: "Spring's shorter learning curve, better performance and open-source nature have helped me learn, innovate and better my output. The fact that the basic version of Spring is just 2MB makes it extremely lightweight and allows developers to use fewer resources. The Inversion of Control (IoC), Aspect-Oriented Programming (AOP) and MVC frameworks in Spring break down development into simpler steps."

3. What are the different modules of a Spring application?

Name as many Spring Modules as possible and be sure to include the important ones.

Example: "There are approximately 20 modules that can be classified into Spring Context, Spring AOP, Spring DAO, Spring JDBC, Spring ORM and Spring MVC."

4. What do you understand by dependency injection and spring IoC container?

Spring uses a special design principle called the inversion of control (IoC), which manages wiring dependencies and the dependency injection is one of its aspects. You are required to have a thorough understanding of both these terms so that you can explain them clearly.

Example: "IoC gives objects dependencies rather than creating or looking for dependent objects. The DI states that we do not create objects manually, but describe the process of their creation instead. When the application is run, the components and services described would be loosely coupled by required classes in the IoC container.

The Spring container forms the basis of the entire framework and uses the DI to manage application components by creating objects, wiring and configuring them and regulating the overall life. The DI ensures that all the components and services of the application are not connected through code; the IoC container does that job. The two types of Dependency Injections are Constructor-Based dependency injection and Setter-Bassed dependency injection. They operate in different methods to give the same result."

5. What are Spring beans?

Spring beans are the basis of the Spring framework. You can explain them and their management by the IoC container.

Example: "Spring beans are Java objects that form the foundation of the application. They are initialised by the Spring IoC container and created with the user-supplied configuration metadata."

6. Explain the different components of Spring applications.

The components include bean class, AOP, Bean Configuration File etc. Explain all the components briefly to describe their purpose.

Example: "A Spring application contains the interface that defines functions, bean class that contains properties, methods and functions. Then there is Spring Aspect AOP which offers cross-cutting functionality. The Bean Configuration File holds all the information of classes and their configuration information. Finally, there is the user program that uses the function."

7. What are some of the design patterns used in Spring?

There are several Spring design patterns, so consider trying to name and explain as many as possible. Try to include at least five patterns in your answer.

Example: "Different design patterns are used by Spring modules and components. The singleton pattern is for singleton-scoped beans, the factory pattern for bean factory classes and the prototype pattern for proto-type scoped beans. There is also the adapter pattern and proxy pattern for Spring web, MVC and AOP support."

8. What is Spring AOP and Spring MVC?

Spring AOP and Spring MVC are two essential frameworks. For clarity, define both frameworks separately instead of comparing them.

Example: "Spring Aspect-Oriented Programming (AOP) helps modularise cross-cutting functions and concerns that are spread across several types and objects. AOP achieves this by adding aspects and enables developers to spend more time on business logic. The Spring Model-View-Controller (MVC) is a request-driven framework that uses IoC to separate and offer loose coupling between the input logic, business logic and UI logic. MVC helps simplify application development by separating the roles and logic neatly and providing reusable business code. MVC also enhances the flexibility and customisation of the development process."

9. What are some commonly-used AOP terminologies?

State as many terms, concepts, elements and features of AOP as possible so a hiring manager understands your knowledge.

Example: "AOP uses terminologies and concepts such as JoinPoint, Advice, Introduction, Pointcut, Aspect, Weaving, Interceptor, AOP Proxy and Target Object."

10. How would you describe the front controller in Spring MVC?

Controllers are integral part of Spring MVC. In your answer, clearly explain the core function of the front controller and requests flow through it.

Example: "The front controller in a typical Spring MVC framework intercepts incoming requests, converts them into internal data structures, forwards them for processing to model and advanced the processed data for rendering to view. In this architecture, the DispatcherServlet acts as front controller and all requests processed by it are annotated with @Controller. Once directed to different controller classes, these requests are executed using the provided input."

11. How is Spring 5 different from the previous versions?

Spring 5 is the latest version and offers many benefits over the previous versions. To demonstrate your expertise, explain these changes and their importance. This also shows that you are aware of the changes and developments taking place in the domain.

Example: "The requirement of Java 8 and above to run Spring 5 and the support for the component index have helped reduce the startup time of large Spring projects. By supporting the Kotlin programming language, Spring 5 is in line with Java's support for functional programming. Spring 5 also has higher levels of modularisation, which eliminates the requirement to import jars that may not have desired functionalities."

12. What are @Qualifier and @Required annotations in Spring?

Annotations are tags that specify metadata attached with class, interface and fields to provide extra data that is used by the compiler and JVM. @Qualifier and @Required are two commonly used annotations in Spring. You are required to explain their usage and properties in your response.

Example: "When more than one bean of the same type is created but only one of them needs to be wired with a specific property, the @Qualifier annotation is used alongside @Autowired to specify which bean requires to be wired.

The @Required annotation is used to bean property setter methods. @Required indicates that the affected property needs to be populated at the time of configuration using an explicit value in the definition or by autowiring. In case the bean has not been populated, the container would throw BeanInitialisationException."

What Are Other Common Spring Interview Questions?

Here are some more Spring Java interview questions that a hiring manager or developer may ask:

What is the difference between tight and loose coupling?
What Is Spring Security?
How are transactions enabled in Spring?
Explain the difference between BeanFactory and ApplicationContext.
How to provide the configuration metadata to the Spring container?
What are the drawbacks of Autowiring?
What is a Dirty Read transaction?
How is the order of advice controlled in Spring AOP?
Explain the differences between Spring and Spring Boot.
What is the Spring Boot dependency management system?
Describe the Hibernate ORM Framework.
What is the role of ViewResolver class?
Explain the meaning of Reactive Programming.
What are the different types of annotations in Spring?
Explain a few Advice types in Spring AOP.
What makes Spring AOP different from AspectJ AOP?
What is the meaning of Proxy in Spring?
What is the Bean lifecycle in the Spring framework?
Explain the meaning of an Embedded Server in Spring Boot.
How is event handling undertaken in Spring?
What is Spring DAO support?
Define Spring Webflux.
How would you enable annotation-based Autowiring?
Explain the difference between FileSystemResource and ClassPathResource.
Compare Spring, Spring Boot and Spring MVC.
What do you understand by Spring Bean Autowiring?
What are the different bean scopes that are supported by Spring?
What are the approaches for database access in Spring JDBC API?

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