Introduction Java Spring Interview Questions And Answers
Java Spring framework is a lightweight framework, most popular, and it is an open-source Java platform. It provides comprehensive architecture and infrastructure support in such a way that it should be very easy and rapidly to develop robust Java applications. The Java Spring framework can also be called a framework of frameworks since it is designed to support various other frameworks such as Hibernate, Struts, EJB, Tapestry, JSF, etc. This can be defined as an organizer where we can find a solution for various technical issues. The Java Spring framework is considered one of the most powerful and flexible frameworks designed to build robust Java applications.
The Java Spring framework includes several modules like IOC, DAO, AOP, ORM, Context, WEB MVC, etc. Spring Framework basically 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 which allows a developer to focus on business logic and other features. Even though the framework is a little old, it keeps getting updated and streamlined continuously.
If you are looking for a job related to Java Spring, you need to prepare for the 2021 Java Spring Interview Questions. It is true that every interview is different as per the different 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 are going to look at some of the most important and top 2021 Java Spring Interview Questions that are frequently asked in an interview. All these questions are divided into two parts are as follows:
Part 1 –Java Spring Interview Questions (Basic)
This first part covers basic Interview Questions and Answers
Q1. What is a Spring Framework?
Java Spring framework is a lightweight framework, most popular, and it is an open-source Java platform. It is a widely used Java EE framework. Spring Framework basically works on two design principles, i.e., Dependency Injection and Aspect-Oriented Programming.
The core features of spring are used to in developing any type of Java application easily and rapidly. It promotes good practice on programming by enabling a POJO-based programming model.
Q2. List some of the important advantages of Spring Framework?
There are the basic Java Spring Interview Questions asked in an interview. It basically works on two design principles, i.e., Dependency Injection and Aspect-Oriented Programming.
Below are some of the important features:
- Lightweight: Java Spring is very lightweight in its size and transparency. It weighs around 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 by using the technique known as Inversion of Control. In this process, objects give their dependencies instead of creating or looking for dependent objects.
- Aspect-oriented (AOP): Java Spring provides support for 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 the development of a project.
- MVC Framework: Java Spring is designed with an MVC web application framework that is built on core Spring functionality. The configuration of this MVC framework is very high and is done by using strategy interfaces and also 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 provides the best Integration services.
- Java Spring framework supports many operations like JDBC operations, transaction management, Exception Handling, File uploading, etc., with very minimal configurations.
Q3. List some of the important disadvantages of Spring Framework?
The Spring framework is designed, and it includes most of the Enterprise applications infrastructure functionalities in it.
Below are some of the important disadvantages:
- Java Spring provides all the facilities to the developers to build/develop java enterprise applications using POJOs (Plain Old Java Object). The important advantage of developing the applications using POJO is that developers will be able to replace enterprise containers. They will be having 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 the existing technologies like Java mail, servlets, JSP, JDBC, RMI, JNDI, and JMS, etc. It makes to simplify the web application development process.
- The Java Spring WEB framework is a very well-designed web MVC framework, which provides a great replacement for a legacy web framework.
- Java Spring has a special feature that it can eliminate the singleton creation and factory classes used in it.
- Java Spring allows a system to maintain a consistent transaction management interface that can make scale up to global transactions (using JTA) and scale down to a local transaction.
- Java Spring application is very user-friendly. It is used to develop many and different applications such as Web applications, standalone GUI applications, standalone applications, and applets. Also to develop 2 tier – n-tier architecture and distributed applications.
- Java Spring supports both annotation and XML configurations services.
Q4. What are Spring sub-projects in Java Spring Framework, and also describe them in brief?
- 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 the implementation of a web module using the Model View Controller design pattern.
- AOP module – implementation of object-oriented programming allows defining a clean method-interceptors and pointcuts in the project.
Q5. What do you mean by Dependency Injection?
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 also 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 and
- 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?
Below is the list of some of the important Spring Framework modules are:
- Spring Context – This module used for the dependency injection process.
- Spring AOP – This module helpful for aspect-oriented programming.
- Spring DAO – Spring DAO module used for database operations by using DAO pattern
- Spring JDBC – Spring JDBC 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 is helpful in developing web applications and web services, etc.
Q7.How beans are injected in Spring. What is the best way of injecting beans and why?
There are the advanced Java Spring Interview Questions asked in an interview. Java Objects which are initialized by the Spring IoC container is 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
The configuration for this process can be done by using XML files or annotations.
The most common and effective approach for injecting beans is to use constructor arguments. This is used for mandatory dependencies, and for optional dependencies, we can use setters. The Constructor arguments injection process allows injecting the values to immutable fields, and that makes it easier for testing.
Q8. How does Spring support by bean scopes and explain them?
Totally there are five scopes, followed by Spring Framework supports, in that three are available only if the end-user uses 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: In this, 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?
Spring Security is considered as a separate module in the Spring framework. It mainly focuses on providing authorization and authentication processes in Java applications. It also handles most of the common security breaches/threats like CSRF attacks.
@EnableWebSecurity is a simple annotation to use Spring Security in web applications.
Let us move to the next Java Spring Interview Questions
Q10. What do you mean by MultipartResolver, and when is it used?
The MultipartResolver is a strategy interface; it is used for uploading multipart files in a web application.
There are two concrete MultipartResolver are included in Spring:
- CommonsMultipartResolver: which is used to Upload Jakarta Commons Files
- StandardServletMultipartResolver: It is used for Servlet 3.0 Part multipart request parsing.
This has been a guide to the List Of Java Spring Interview Questions and Answers so that the candidate can crackdown on these Interview Questions easily. Here in this post, we have studied top Java Spring Interview Questions, which are often asked in interviews. You may also look at the following articles to learn more –