Java Spring Interview Questions

The following article provides an outline for Java Spring Interview Questions. Java Spring framework is the most popular lightweight framework, and it is an open-source Java platform. It provides comprehensive architecture and infrastructure support, so developing robust Java applications should be straightforward and rapid. The Java Spring framework, also known as a framework of frameworks, supports various other frameworks such as Hibernate, Struts, EJB, Tapestry, JSF, etc. It is an organizer where developers can find solutions for various technical issues. Developers widely regard the Java Spring framework as one of the most powerful and flexible frameworks for constructing robust Java applications.

The Java Spring framework includes modules like IOC, DAO, AOP, ORM, Context, WEB MVC, etc. Spring Framework works on two design principles, i.e., Dependency Injection and Aspect-Oriented Programming. One of the main advantages of using Java Spring is that the inbuilt Spring framework will handle most of the low-level features of building a web application, allowing a developer to focus on business logic and other features. Even though the framework is a little old, it keeps updating and continuously streamlining.

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If you are looking for a job related to Java Spring, you must prepare for the 2023 Java Spring Interview Questions. Every interview is indeed different as per the various job profiles. Here, we have prepared the important Java Spring Interview Questions and Answers, which will help you get success in your interview.

In this article, we will explore some of the most important and top 2023 Java Spring interview questions frequently asked in interviews.

All these questions are divided into two parts.

Part 1 – Java Spring Interview Questions (Basic)

This first part covers basic Interview Questions and Answers:

Q1. What is a Spring Framework?

Answer:

Java Spring framework is the most popular lightweight framework, and it is an open-source Java platform. It is a widely used Java EE framework. Spring Framework works on two design principles, i.e., Dependency Injection and Aspect-Oriented Programming.

The core features of Spring enable developers to easily and rapidly develop any Java application. It promotes good practice in programming by enabling a POJO-based programming model.

Q2. List some of the important advantages of Spring Framework?

Answer:

It works on two design principles, i.e., Dependency Injection and Aspect-Oriented Programming.

Below are some of the advantages:

• Lightweight: Java Spring is very lightweight in size and transparency. It weighs only 1MB when we consider the basic version of the spring framework. And processing overhead in it is also very negligible.
• Inversion of control (IOC): Loose coupling in spring can be achieved using the technique called Inversion of Control. In this process, objects give their dependencies instead of creating or looking for dependent objects.
• Aspect-oriented (AOP): Java Spring supports situational-oriented programming and enables characterized development by separating application business logic from system requirement services.
• Container: Java Spring includes and manages the complete lifecycle and configuration of all application objects in project development.
• MVC Framework: Java Spring is designed with an MVC web application framework built on core Spring functionality. The configuration of this MVC framework is very high and is done using strategy interfaces and provides multiple view technologies like Tiles, JSP, iText, Velocity, and POI.
• JDBC Exception Handling: The JDBC layer in the spring helps the error-handling strategy by providing an exception hierarchy. By integrating with JDO, Hibernate, and iBATIS, Spring offers the best Integration services.
• Java Spring framework supports many operations like JDBC operations, Transaction management, Exception Handling, File uploading, etc., with minimal configurations.

Q3. List some of the important disadvantages of Spring Framework?

Answer:

The Spring framework is designed to include most of the Enterprise applications’ infrastructure functionalities.

Below are some of the disadvantages:

• Java Spring provides all the facilities to the developers to build/develop Java enterprise applications using POJOs (Plain Old Java Objects). The important advantage of developing applications using POJO is that developers can replace enterprise containers. They will have the option of using a robust servlet container and need not have any enterprise container like an application server.
• Java Spring facilitates an abstraction layer on existing technologies like Java mail, servlets, JSP, JDBC, RMI, JNDI, and JMS. It makes to simplify the web application development process.
• The Java Spring WEB framework is a highly well-designed web MVC framework that offers an excellent alternative to legacy web frameworks.
• Java Spring has a special feature that can eliminate the singleton creation and factory classes used.
• Java Spring allows a system to maintain a consistent transaction management interface that can scale up to global transactions (using JTA) and down to local transactions.
• Java Spring application is very user-friendly. It is used to develop many applications, such as Web, standalone GUI, and applets. Also, to develop 2-tier – n-tier architecture and distributed applications.
• Java Spring supports both annotation and XML configuration services.

Q4. What are Spring sub-projects in Java Spring Framework, and describe them briefly.

Answer:

• Core – Core is a key module in a framework that provides the fundamental parts of the framework, such as IoC or DI.
• JDBC – Spring sub-projects module enables a JDBC-abstraction layer which removes the JDBC coding for specific vendor databases for better performances.
• ORM integration – This integration facilitates the integration layers for object-relational mapping APIs, such as JDO, JPA, and Hibernate features.
• Web – For a web-oriented integration module, it provides the features like Servlet listeners, multipart file upload, and context functionalities of web-oriented applications.
• MVC framework – This is implementing a web module using the Model View Controller design pattern.
• AOP module – Implementation of object-oriented programming allows defining clean method-interceptors and pointcuts in the project.

Q5. What do you mean by Dependency Injection?

Answer:

Dependency Injection is used as a design pattern, and in the Spring framework, it provides permission to a web developer to remove the hard-coded dependencies and make the application extendable, loosely coupled, and maintainable. Dependency injection patterns can also be used/implemented to move the dependency resolution from compile-time to runtime.

There are some benefits of using Dependency Injection, and they are:

• It makes the separation of Concerns
• Allows Boilerplate Code reduction
• Helps in Configurable components
• It is very easy for unit testing

Part 2 – Java Spring Interview Questions (Advanced)

Let us now have a look at the advanced Interview Questions.

Q6. Name some of the important Spring Modules.

Answer

Below is the list of some of the important Spring Framework modules:

• Spring Context –Developers use this module for the dependency injection process.
• Spring AOP – This module is helpful for aspect-oriented programming.
• Spring DAO –Developers use the Spring DAO module to perform database operations using the DAO pattern.
• Spring JDBC – Spring JDBC is used for JDBC connection and DataSource support.
• Spring ORM – This module is important for ORM tools support.
• Spring Web Module – Spring Web module is used for creating web applications.
• Spring MVC – Spring Model-View-Controller implementation helps develop web applications, web services, etc.

Q7. How beans are injected in Spring. What is the best way of injecting beans, and why?

Answer:

Java Objects initialized by the Spring IoC container are known as Spring Beans. To get the Spring Bean instance, we use Spring ApplicationContext.

There are only a few different options that exist to inject the beans in Spring:

• Setter Injection
• Constructor Injection
• Field Injection

You can configure this process using XML files or annotations.

The most common and effective approach for injecting beans is to use constructor arguments. Developers use this for mandatory dependencies, while setters can be used for optional dependencies. The Constructor arguments injection process allows injecting the values to immutable fields, making testing easier.

Q8. How does Spring support by bean scopes, and explain them?

Answer:

The Spring Framework supports five scopes, with three only available when the end-user utilizes a web-aware Application Context.

• Singleton: The bean definition will get scopes to a single instance per Spring IoC container by Singleton.
• Prototype: In this, a scope will happen only for a single bean definition to have any number of object instances.
• Request: In this, a bean definition scopes to an HTTP request. It is valid only in the process of web-aware Spring ApplicationContext.
• Session: A bean definition scopes to an HTTP session. It is valid only in the process of web-aware Spring ApplicationContext.
• Global-session: Scopes will happen from bean definition to a global HTTP session. It is valid only in the process of web-aware Spring Application Context.

Q9. What is Spring Security?

Answer:

Spring Security is a separate module within the Spring framework. It mainly focuses on providing authorization and authentication processes in Java applications. It also handles the most common security breaches/threats like CSRF attacks.

@EnableWebSecurity is a simple annotation to use Spring Security in web applications.

Q10. What do you mean by MultipartResolver, and when is it used?

Answer:

The MultipartResolver is a strategy interface; Developers use it for uploading multipart files in a web application.

There are two concrete MultipartResolver in Spring:

• CommonsMultipartResolver: Use to Upload Jakarta Commons Files.
• StandardServletMultipartResolver: Use for Servlet 3.0 Part multipart request parsing.

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