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Table of contents
1.
Introduction
2.
Beginner Level Spring Interview Questions
2.1.
1. What do you mean by Spring framework?
2.2.
2. What are the primary advantages of using the Spring Framework?
2.3.
3. What do you understand by Inversion of Control (IoC) in Spring?
2.4.
4. What is dependency injection(DI), and what are its types?
2.5.
5. What is the use of @SpringBootApplication annotation?
2.6.
6. What do you mean by AOP in Spring?
2.7.
7. What are the types of containers that are present in Spring?
2.8.
8. What do you mean by Spring Boot?
2.9.
9. What is the use of @Autowired annotation in Spring?
2.10.
10. What is the use of @Transactional annotation in Spring?
3.
Intermediate Level Spring Interview Questions
3.1.
11. What do you understand by Spring MVC?
3.2.
12. What do you mean by DispatcherServlet in a Spring MVC application?
3.3.
13. What is the use of the @ModelAttribute annotation in Spring MVC?
3.4.
14. What are the differences between BeanFactory and ApplicationContext?
3.5.
15. What do you understand by Spring Security?
3.6.
16. What is the use of the Spring WebFlux module, and how is it different from Spring MVC?
3.7.
17. What are the differences between Spring Boot and Spring?
3.8.
18. What are the different types of bean scopes in Spring?
3.9.
19. How do you configure logging in to a Spring Boot application?
3.10.
20. What kind of information is saved under the application.properties file?
4.
Advanced Level Spring Interview Questions
4.1.
21. How is Spring integrated with other technologies like Hibernate, JPA, and RESTful web services?
4.2.
22. How can we implement caching in a Spring Boot application?
4.3.
23. How can we handle exceptions in a Spring Boot application?
4.4.
24. What do you mean by Spring Interceptors?
4.5.
25. What are the different types of advice available in AOP?
4.6.
26. What do you mean by Spring Data JPA? How does it work, and what are some of its advantages over traditional JDBC?
4.7.
27. What are @Component, @Repository, and @Service annotations in Spring?
4.8.
28. What are the differences between @PathVariable and @RequestParam annotations in Spring MVC?
4.9.
29. What is Spring HATEOAS?
4.10.
30. What is reactive programming, and how does it relate to Spring WebFlux?
5.
Frequently Asked Questions
5.1.
How to prepare for Java Spring Interview?
5.2.
What is Dependency Injection and IoC in Spring?
5.3.
Is Dao a module of Spring?
5.4.
Why Spring is the best framework? 
6.
Conclusion
Last Updated: Jun 12, 2024
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Spring Interview Questions and Answers (2023)

Author Narayan Mishra
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Introduction

Are you preparing for a Spring interview? If yes, then you are at the right place. The Spring framework was developed by Rod Johnson and his team in 2002. It was developed as an alternative to the heavy-weight Enterprise JavaBeans (EJB) framework, which was prevalent then. This framework aims to simplify the development of enterprise applications. It provides a lightweight and flexible programming model.

spring interview questions

In this article, we will discuss Spring Interview Questions and Answers. We will discuss interview questions in different levels, such as beginner, intermediate, and advance levels.

Also read, project manager interview questions

Beginner Level Spring Interview Questions

In this section, we will discuss beginner-level Spring interview questions.

1. What do you mean by Spring framework?

Spring is a popular open-source framework. It is used for building enterprise-level Java applications. It gives a comprehensive programming and configuration model for modern Java-based enterprise applications. Using this framework, we can develop web, mobile, and microservices applications.

2. What are the primary advantages of using the Spring Framework?

The following are the primary advantages of using the Spring Framework:

  • The Spring framework has a variety of templates for Hibernate, JDBC, and JPA technologies. This strategy eliminates the need for developers to define sophisticated code.
     
  • Using a spring framework with a dependency injection technique, it is simple to test the complete application. The server is required to execute the EJB or Struts application.
     
  • Spring is simple to implement using the Plain Old Java Object (POJO) technique since it does not need the developer to inherit specific classes or implementations on any interface.
     
  • It is simple to integrate the framework and assist the creation of JavaEE-based applications using Dependency Injection.

3. What do you understand by Inversion of Control (IoC) in Spring?

It is a core design principle of the Spring Framework, which uses dependency injection (DI). It's a process of inverting the control of object creation and management from the application code to an external container or framework.

4. What is dependency injection(DI), and what are its types?

It is a fundamental concept in the Spring Framework. DI is a design pattern. In this design pattern, an object's dependencies are provided to it by an external source rather than the object creating or looking up its dependencies. There are three types of DI in Spring:

  • Constructor Injection: Constructor injection is the process of passing a class's dependencies through the constructor.  When your class has a dependency that the class needs to function properly, you should utilize constructor injection.  If your class cannot function without a dependency, inject it through the constructor.
     
  • Property Injection: Property Injection, on the other hand, produces Temporal Coupling, and when designing Line of Business apps, dependencies should never be optional: instead, utilize the Null Object model.  In 98% of cases, property injection is deemed harmful since it hides dependencies and there is no guarantee that the object will be injected when the class is formed. 
     
  • Method Injection: Method injection is beneficial in two situations: when the implementation of a dependent changes and when the dependency must be refreshed after each use. In both circumstances, the caller must determine which implementation to send to the method.

5. What is the use of @SpringBootApplication annotation?

The @SpringBootApplication annotation is a meta-annotation. It is used in Spring Boot applications to enable various auto-configuration features. It is also used to bootstrap the application. 

It combines three annotations:

  1. @Configuration
     
  2. @EnableAutoConfiguration
     
  3. @ComponentScan

6. What do you mean by AOP in Spring?

AOP stands for Aspect-Oriented Programming. It is a programming paradigm that aims to modularize cross-cutting concerns into reusable and modular components. These concerns can be logging, security, and transaction management. AOP accomplishes this by separating concerns into distinct units called "aspects," which can be applied to multiple objects or components.

7. What are the types of containers that are present in Spring?

The following are the two primary types of containers in Spring:

  1. BeanFactory Container: This is the core container in Spring that provides basic functionality for managing beans. 
     
  2. ApplicationContext Container: This is a more feature-rich container that extends the functionality of the BeanFactory container. 

8. What do you mean by Spring Boot?

It is a framework which is built on top of the Spring Framework. It provides a simplified way to develop and deploy Spring-based applications. Spring Boot gives an opinionated approach to application configuration. It also reduces the amount of boilerplate code that developers need to write.

9. What is the use of @Autowired annotation in Spring?

@Autowired annotation is used to automatically inject dependencies into the Spring-managed bean. It allows Spring to automatically detect the dependencies that a bean requires. It injects the dependencies at runtime without the need for manual configuration.

10. What is the use of @Transactional annotation in Spring?

@Transactional annotation marks a method, or an entire class, as transactional. It defines the boundaries of a transaction. This is a unit of work that should be executed atomically and consistently.

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Intermediate Level Spring Interview Questions

In this section, we will discuss intermediate-level Spring interview questions.

11. What do you understand by Spring MVC?

Spring MVC stands for Spring Model-View-Controller. It is a powerful and flexible web framework. It is part of the Spring Framework. Spring MVC follows the Model-View-Controller design pattern, which separates the application into three components:

  1. Model: It represents the application data and business logic.
     
  2. View: It represents the presentation layer of the application.
     
  3. Controller: It handles user requests and responses and interacts with the model and view.
spring mvc

12. What do you mean by DispatcherServlet in a Spring MVC application?

The DispatcherServlet in a Spring MVC application is a special servlet. It acts as the front controller for all incoming HTTP(Hypertext Transfer Protocol) requests. It is the heart of the Spring MVC framework. It is also responsible for handling and routing all requests to the appropriate controller. It handles and routes based on the request URL and HTTP method.

When a request is made to a Spring MVC application, it is first intercepted by the Servlet container. The container then passes the request to the DispatcherServlet, which is configured in the web.xml file of the Spring MVC application.

13. What is the use of the @ModelAttribute annotation in Spring MVC?

The @ModelAttribute annotation is used to bind the request parameters to a model attribute. The attribute can then be used by the view to render the response.

Whenever a form is submitted in a Spring MVC application, the values of the form fields are sent as request parameters. The @ModelAttribute annotation in Spring MVC can be used to automatically populate a model attribute with the values of the corresponding form fields.

14. What are the differences between BeanFactory and ApplicationContext?

Both BeanFactory and ApplicationContext are core components of the Spring Framework. They serve as a container for Spring beans. 

However, there are primary differences between them, as mentioned below:

BeanFactoryApplicationContext
It provides basic support for dependency injection and bean lifecycle management. It initializes beans lazily, which means that beans are only created when they are requested.It initializes beans eagerly, which means that all beans are created at startup.
It can load resources like XML configuration files, property files, and annotations from any location accessible by the classloader.It supports a wider range of resource types, such as JNDI objects, JDBC DataSource, and JMS Destination.
It does not provide support for bean post-processors.It supports bean post-processors, which can modify or enhance the functionality of beans after they are initialized.
It does not provide support for internationalization.It provides support for internationalization through the use of resource bundles, message sources, and locale resolvers.

15. What do you understand by Spring Security?

Spring Security is a powerful and highly customizable security framework. It provides authentication, authorization, and other security features for Spring-based applications. It is built on top of the Spring framework. It offers various security features, such as encryption, session management, and access control.

Spring Security works by intercepting incoming HTTP requests. It applies a set of security rules and policies to determine whether the request is allowed or not. This is achieved through a combination of filters, interceptors, and configuration settings.

16. What is the use of the Spring WebFlux module, and how is it different from Spring MVC?

The Spring WebFlux module is a reactive web framework. It is built on top of the Spring Framework. It is used for building asynchronous, non-blocking, and event-driven web applications. It provides a functional programming model. It also supports reactive streams, which enable developers to write highly scalable and performant web applications.

Spring WebFlux differs from Spring MVC in several ways:

  • Programming model
     
  • Concurrency model
     
  • Reactive streams

17. What are the differences between Spring Boot and Spring?

Spring Boot and Spring are two related but distinct projects within the Spring ecosystem. Here are the main differences between the two:

Spring BootSpring
It provides a "convention over configuration" approach that allows developers to quickly create and configure a Spring application with minimal boilerplate. It requires developers to configure many aspects of the application explicitly.
It includes a built-in dependency management system that automatically manages versions and conflicts of Spring and other third-party libraries.It requires developers to manage dependencies manually.
It is designed to be a standalone framework that can be used to create self-contained, production-ready applications.It is a more general-purpose framework. It can be used for various applications and use cases.
It is easy to use and requires minimal configuration to get up and run.It can be more complex to use and requires a deeper understanding of the framework.
It is an opinionated framework that provides a set of preconfigured defaults and best practices for building applications.It is a more modular framework. It provides a wide range of building blocks and allows developers to assemble them customized.

18. What are the different types of bean scopes in Spring?

There are several types of bean scopes in Spring. You can use them to define the lifecycle of a bean. The following are the different types of bean scopes in Spring:

  • Singleton: This is the default scope in Spring. 
     
  • Prototype: If you need to create a new instance of a bean whenever requested, you should use the prototype scope.
     
  • Request: If you need to create a bean that is used only for the duration of an HTTP request, you should use the request scope.
     
  • Session: If you need to create a bean that is used only for the duration of an HTTP session, you should use the session scope.
     
  • Global Session: If you need to create a bean that is used only for the duration of a global HTTP session, you should use the global session scope.
     
  • Application: If you need to create a bean that is used throughout the entire application, you should use the application scope.

19. How do you configure logging in to a Spring Boot application?

Spring Boot provides built-in support for configuring logging into an application. 

The following are the steps to configure logging into a Spring Boot application:

  1. Add the logging dependencies.
     
  2. Configure the logging level.
     
  3. Customize the logging configuration.
     
  4. Add log statements to the code.
     
  5. View the logs.

20. What kind of information is saved under the application.properties file?

The application.properties file is used in Spring Boot applications to configure various properties related to the application, such as database configuration, server port, logging configuration, etc. Some examples of the properties that can be configured in the application.properties file are:

Server Configuration:

server.port=8080
server.servlet.context-path=/myapp

 

Database Configuration:

spring.datasource.url=jdbc:mysql://localhost/mydb
spring.datasource.username=user
spring.datasource.password=password
spring.jpa.hibernate.ddl-auto=create-drop

 

Logging Configuration:

logging.level.root=INFO
logging.file=myapp.log

 

Security Configuration:

spring.security.user.name=user
spring.security.user.password=password


These are just a few examples of the properties. These properties can be configured in the application.properties file. Spring Boot provides many more configuration options. Those options can be used to customize the behavior of the application. The properties specified in the application.properties file are loaded by Spring Boot at runtime. They are used to configure the application.

Advanced Level Spring Interview Questions

In this section, we will discuss Advance level Spring interview questions.

21. How is Spring integrated with other technologies like Hibernate, JPA, and RESTful web services?

Spring provides several integration mechanisms to work seamlessly with other technologies. These technologies can be Hibernate, JPA(Java Persistence API), and RESTful web services. Here's how Spring integrates with each of these technologies:

  • Hibernate Integration: Spring provides integration with Hibernate through the Spring ORM(Object-relational mapping) module. The ORM module provides a HibernateTemplate class. This class simplifies the use of Hibernate APIs and provides a simplified API for performing CRUD(CREATE, READ, UPDATE, and DELETE) operations, query execution, and transaction management. Spring also supports declarative transaction management for Hibernate using annotations or XML configuration.
     
  • JPA Integration: Spring integrates with JPA through the Spring Data JPA module. This module provides a repository abstraction. This repository abstraction simplifies the use of JPA APIs. The repository abstraction provides a simplified API for performing CRUD operations and query execution. Spring also supports declarative transaction management for JPA using annotations or XML configuration.
     
  • RESTful Web Services Integration: Spring integrates RESTful web services through the Spring MVC module. The Spring MVC module supports developing RESTful web services using annotations or XML configuration. Spring MVC supports using the @RestController annotation to create RESTful controllers. These controllers can handle requests and return responses in various formats, such as JSON, XML, or plain text. Spring also provides support for RESTful client development using the RestTemplate class.

22. How can we implement caching in a Spring Boot application?

Spring Boot provides built-in support for implementing caching. We can implement caching using several caching providers such as Ehcache, Redis, and Caffeine. Here's how to implement caching in a Spring Boot application using the Spring Cache Abstraction:

  1. To use caching in your Spring Boot application, you must add the appropriate caching dependencies to your build file. 
     
  2. To enable caching, you need to add the @EnableCaching annotation to one of your configuration classes. 
     
  3. To configure caching, you must define one or more cache managers. A cache manager is responsible for creating and managing caches. You can configure a cache manager by implementing the CachingConfigurer interface. You can also configure it by using the CacheManagerCustomizer interface.
     
  4. Once you've enabled and configured caching in your Spring Boot application, you can use caching by adding the @Cacheable annotation to methods that return values that can be cached. 

23. How can we handle exceptions in a Spring Boot application?

In a Spring Boot application, we can handle exceptions in many ways:

  • We can use the @ExceptionHandler annotation. This annotation is used to handle exceptions thrown by a specific controller method or by any controller in your application. 
     
  • We can use the @ControllerAdvice annotation to define a global exception handler. It can handle exceptions thrown by any controller in your application.
     
  • Spring Boot provides default error handling. It automatically displays a user-friendly error page when an exception is thrown. We can customize this error page by creating a custom error page. We can also configure Spring Boot to use it.
     
  • We can create custom error pages for specific HTTP status codes or for specific exception types. To do this, we can create an error page template and configure Spring Boot to use it for specific error codes or exceptions.
     
  • We can use the @ResponseStatus annotation. This annotation is used to specify the HTTP status code that should be returned whenever a specific exception is thrown.

24. What do you mean by Spring Interceptors?

Spring Interceptors are a feature in the Spring Framework. They allow you to intercept and modify incoming HTTP requests and outgoing HTTP responses. They are a type of aspect-oriented programming (AOP) functionality. They provide a way to add standard behavior or logic to multiple controllers or actions in a Spring MVC application.

They are implemented as classes. These classes implement the HandlerInterceptor interface. This interface defines three methods. These three methods can be used to intercept HTTP requests and responses:

  1. preHandle()
     
  2. postHandle()
     
  3. afterCompletion()
     

Spring Interceptors can be registered globally or for specific controllers. They can be used for various purposes, such as authentication, caching, logging, or performance monitoring.

25. What are the different types of advice available in AOP?

There are several types of advice in AOP. They can be used to separate cross-cutting concerns from the main logic of a program. The different types of advice in AOP are:

  1. Before advice: This advice executes before the actual method execution. It is used to perform some pre-processing before invoking the actual method.
     
  2. After returning advice: This advice executes after the successful completion of execution of the actual method and returns a value. It is used to perform some post-processing on the returned value.
     
  3. After throwing advice: This advice executes if an exception is thrown by the actual method. It is used to handle the exception and perform some cleanup activities.
     
  4. After advice: This advice executes after the completion of execution of the actual method, whether it is normally returning or throwing an exception. It is used to perform some cleanup activities.
     
  5. Around advice: This advice executes around the actual method. It can control the invocation of the actual method. It can also perform some pre-processing and post-processing and can handle exceptions.

26. What do you mean by Spring Data JPA? How does it work, and what are some of its advantages over traditional JDBC?

Spring Data JPA is a framework. It provides an abstraction layer on top of the Java Persistence API (JPA). It makes easy the process of accessing and managing relational databases using JPA. Developers can write less boilerplate code and focus on the business logic of their application with Spring Data JPA.

Spring Data JPA works by automatically generating JPA queries. These queries are based on the method name and parameters of the repository interface methods. It provides a set of standard CRUD operations, which can be extended to include custom queries. Developers can also use JPA's query language, JPQL(Java Persistence query language), or native SQL queries.

Some of the advantages of using Spring Data JPA over traditional JDBC(Java database connectivity) include the following:

  • Simplified data access
     
  • Increased productivity
     
  • Improved maintainability
     
  • Better code organization

27. What are @Component, @Repository, and @Service annotations in Spring?

The @Component, @Repository, and @Service annotations in Spring are used to indicate the role of a class in the application. All three annotations are used to mark a class as a Spring bean.

  • @Component: This is the most general-purpose annotation. It can be used to mark any class as a Spring bean. It indicates that a class is a general-purpose component, such as a utility class or a data access object. It is the default annotation for any class that does not fit into one of the more specific categories.
     
  • @Repository: This annotation indicates that a class is a data access object (DAO). It marks classes interacting with a database or another data store. The main advantage of using the @Repository annotation is that it enables exception translation.
     
  • @Service: This annotation indicates that a class is a service layer component. It is used to mark classes that contain business logic, such as transactional services or other application services. 

28. What are the differences between @PathVariable and @RequestParam annotations in Spring MVC?

The @PathVariable and @RequestParam annotations in Spring MVC. They are used to extract parameters from the incoming HTTP request. While both annotations are mainly used to handle request parameters, there are some differences in their usage and functionality.

  • PathVariable: This annotation is used to extract a variable from the URI(Universal Resource Identifier) path of the request. It is used to handle requests that contain dynamic values, such as RESTful APIs. The @PathVariable annotation maps a variable in the URI to a method parameter. For example, if the URI is "/employees/{empId}", the @PathVariable annotation can be used to extract the value of "empId" from the URI and use it as a method parameter.
     
  • @RequestParam: This annotation extracts a parameter from the query string or form data of the request. It is used to handle requests that contain fixed parameters, such as search or filter parameters. The @RequestParam annotation maps a parameter in the request to a method parameter. For example, if the request contains a parameter "number" with value "1", the @RequestParam annotation can be used to extract the value of "number" and use it as a method parameter.

29. What is Spring HATEOAS?

Spring HATEOAS is a subproject of the Spring Framework. It provides support for building hypermedia-driven RESTful web services. HATEOAS stands for "Hypermedia As The Engine Of Application State". It refers to the concept of including hypermedia links in the response of a RESTful service to enable clients to navigate the service's resources.

Spring HATEOAS provides a set of classes and annotations. This set of classes and annotations can be used to create hypermedia links and embed them in the response of a RESTful service. These links provide information about the resources available in the service and the operations that can be performed on them. By including these links in the response, clients can navigate the service's resources without having prior knowledge of the service's API.

30. What is reactive programming, and how does it relate to Spring WebFlux?

Reactive programming is a programming paradigm. It allows for the efficient and scalable handling of large amounts of data in real time. It is characterized by the use of asynchronous and non-blocking data streams. This can handle large amounts of data with lower resource utilization and better performance than traditional blocking I/O.

Spring WebFlux is a reactive web framework. It was introduced in Spring 5. It supports reactive programming in Spring. It is built on top of the reactive streams API. It provides a fully non-blocking and reactive API for handling HTTP requests and responses. Developers can build reactive, event-driven, and non-blocking web applications with Spring WebFlux.

Frequently Asked Questions

How to prepare for Java Spring Interview?

Study essential concepts such as dependency injection, Spring MVC, AOP, and security to prepare for a Java Spring interview. Work on real-world projects while practicing coding exercises and answering common interview questions.  

What is Dependency Injection and IoC in Spring?

Dependency Injection is a technique for supplying dependencies, and Inversion of Control is the ultimate effect of Dependency Injection. IoC is a design approach in which the program's control flow is inverted. One of the subtypes of the IOC principle is dependency injection.

Is Dao a module of Spring?

The Spring-DAO module is not a spring module. It does not include any interfaces or templates for gaining access to the data. One significant change that must be made when using Spring DAO is that it must be annotated with @Repository.

Why Spring is the best framework? 

Due to its comprehensive features, such as dependency injection, aspect-oriented programming, security, and MVC support, Spring is regarded as one of the greatest Java frameworks. Its modular, adaptive structure enables applications that are strong, scalable and maintained.

Conclusion

In this article, we have discussed Spring Interview Questions and Answers. We have discussed interview questions in three categories: beginner, intermediate, and advance. You can check out our other interview questions blogs:

 

You can also consider our Spring Boot Course to give your career an edge over others.

Happy Learning!!

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