Spring Boot Interview Questions | 30 best questions ever asked in 2021 interviews!

Preparing for Spring boot interview. Here is a comprehensive list of the 30 best Spring boot interview questions ever asked in 2021. Read on!

Spring boot interview questions

Spring boot is one of the trending topics in the world of modern technology, related to Java Application development. If you are aspiring for a profession related to Java designer or developer, then you must be aware of the Spring boot interview questions, typically asked by recruiting companies and hiring managers.

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Top 5 Spring Boot interview questions

In this section, we will discuss the top 5 Spring Boot interview questions and their appropriate sample answers. The set of spring boot interview questions and answers will act as a ready reckoner to prepare effectively and efficiently for a spring boot interview.

1. What is the difference between spring and spring boot

Rationale: To understand the basic knowledge of the candidate about spring and spring boot; one of the common spring boot interview questions

Sample Answer: Spring is the name of the framework predominantly being used in Java applications. Its key feature includes inversion control or dependency injection. On the other hand, a spring boot is a module within the framework. Spring boot is advantageous in creating a stand-alone application with minimal configurations.

2. What are the key components of a spring boot framework?

Rationale: Awareness of the experience and expertise of working with a spring boot framework; one of the vital spring boot interview questions

Sample Answer: The spring boot framework comprises seven key components. They are the auto-configuration, version management, starter POMs, component scanning, InMemory Database, embedded server, and actuators.

3. Why spring boot is preferred over spring?

Rationale: To verify whether the candidate has hands-on knowledge of using spring boot in past assignments; one of the mandatory springboot interview questions.

Sample Answer: Spring boot assists in creating an efficient and faster ecosystem for Java applications. It is an extension and component of the spring framework; works by extracting an opinionated view from the platform. Hence the boilerplate configurations are eliminated while creating a spring or java application.

4. What is spring boot used for?

Rationale: To check the detailed knowledge of the spring boot, its features, and the purpose behind its usage; one of the essential questions and answers for experienced professionals.

Sample Answer: Spring boot is essentially used to create a stand-alone application through its microservices. It eliminates the need for complex configurations in XML. The applications are developed faster and in a much easier way. Besides, using spring boot, applications can run independently.

5. Elaborate on Spring vs Maven

Rationale: To ensure the candidate has the requisite knowledge of using Maven and Spring appropriately; one of the popular spring boot interview questions.

Sample Answer: A maven is a tool used for build automation in a CI/CD, DevOps, and Agile mode of working. It stores the spring libraries and acts as a repository for the spring suite framework. Spring is the framework that contains the libraries, configurations, source code for the application.

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Top 5 Spring Rest interview questions

Here is a list of the 5 best Spring Rest interview questions,

1. What is the full form of REST and what is it used for?

Rationale: To verify whether the candidate is aware of the basic concepts of Spring REST; one of the common spring rest interview questions.

Sample Answer: The full form of REST is Representational State Transfer. It can expose web services through HTTP. The resources are transferred via the HTTP protocol to various external applications.

2. Explain in detail the HTTP methods of Spring REST?

Rationale: It is one of the spring web services interview questions that evaluates a candidate’s exposure to HTTP features.

Sample Answer: The key HTTP methods are,

• GET – Used to request and receive a source from the source URL
• POST – Used to submit the data and file to the web service for further processing
• PUT – Used to send the new or updated resource at the target URL

3. Distinguish between @PathVariable and @RequestParam?

Rationale: Vital to check whether the candidate possesses an in-depth understanding of REST concepts; one of the crucial spring boot interview questions.

Sample Answer: @RequestParam consists of the parameters which are added to the URL after the “?”. The syntax consists of a default value, name of the parameter, specifying whether the parameter is mandatory or not and the alias for the attribute. @PathVariable consists of variables added by the “/”.

4. Mention the process of validating the input data in Spring REST?

Rationale: To check the hands-on capability of the candidate in REST operations; one of the spring data interview questions to ask.

Sample Answer: The best answer is to talk about the Hibernate Validator, where the validation for the input data can be customized as per need.

5. What is @ResponseBody used for?

Rationale: Another one of the important spring rest interview questions to ask for checking the detailed knowledge of the candidate.

Sample Answer: The use of @ResponseBody is to accept the value from the controller within the body of the response.

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Top 5 Spring cloud interview questions

Here is a list of the 5 best Spring Cloud interview questions,

1. Define Spring Cloud?

Rationale: One of the important spring cloud interview questions is to check the basic knowledge of the candidate.

Sample Answer: Spring Cloud is defined to be a set of tools for building patterns that are common in systems used for development activities including discovery, configurations, etc.

2. Describe the key features of Spring Cloud?

Rationale: Aids to verify the in-depth knowledge of the candidate on Spring cloud and its usage; one of the crucial spring boot interview questions.

Sample Answer: The key features of spring cloud include routing, service registration, and discovery, load balancing, service to service calls, versioning, and distributed configuration.

3. Explain the concept of load balancing?

Rationale: To verify whether the candidate has clarity on the subject and can apply the same on the job; a must inclusion in the list of spring boot interview questions and answers.

Sample Answer: Distribution of workloads is an important concept in the spring cloud. Load Balancing enables the same across different computing resources like CPUs, computer clusters, network lines, and so on.

4. Define Hystrix?

Rationale: To check the expertise of the candidate on spring cloud and its concepts; one of the crucial spring cloud interview questions.

Sample Answer: Hystrix enables the isolation of access points through its library for latency and fault tolerance. Access points can be remote systems, services, third-party libraries, and so on.

5. Specify the advantages of spring cloud?

Rationale: To understand whether the candidate realizes the need for using Spring cloud; one of the common interview questions on spring boot.

Sample Answer: Spring cloud assists in resolving complexity in distributed systems, reduces redundancy, enables load balancing, and has a service discovery tool.

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Top 5 Spring Boot microservices interview questions

Here is a list of the 5 best Spring Boot microservices interview questions,

1. Describe the role of an actuator in spring boot?

Rationale: One of the common spring boot microservices interview questions to verify the basic knowledge about microservices.

Sample Answer: Actuator plays a vital role in spring boot, helping to access the current state of the application that is running in production.

2. Mention the embedded containers of Spring boot?

Rationale: To verify the conceptual knowledge of the candidate on the subject; one of the crucial spring microservices interview questions.

Sample Answer: The embedded containers are Jetty which is widely used, Tomcat which is an open-source implementation and Undertow which is a flexible web server.

3. What do you understand by Semantic monitoring?

Rationale: To understand the in-depth knowledge of the candidate on microservices; one of the crucial spring boot microservices interview questions.

Sample Answer: Semantic monitoring involves end-to-end monitoring and automated tests of the entire application. It facilitates bug triaging and faster isolation for repair.

4. Explain the need for reports and dashboards in Microservices?

Rationale: The question helps to assess the analytical knowledge of the candidate; one of the preferred spring boot microservices interview questions.

Sample Answer: Reports and dashboards serve the purpose of monitoring and maintaining microservices. They help to check the resources being utilized, services impacted, etc.

5. Can you explain the functioning of the PACT tool?

Rationale: To check the knowledge of advanced concepts in Microservices; one of the interesting spring boot interview questions.

Sample Answer: An open-source tool, PACT aids in verifying the interactions between service providers and consumers. The process is initiated by the consumer service developer who writes a test.

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Top 5 Spring integration interview questions

Here is a list of the 5 best Spring integration interview questions,

1. Define Spring integration?

Rationale: One of the common spring integration interview questions to verify the basic knowledge of the candidate.

Sample Answer: For supporting enterprise integration patterns, spring integration is a vital project. It is lightweight and a programming model that can be decoupled.

2. Define Pipes and Filters?

Rationale: Aids in verifying the in-depth knowledge of the candidate on spring integration architecture; one of the preferred spring boot interview questions.

Sample Answer: Pipes are the transport that delivers messages in an asynchronous communication system. Filters are the subsystems that produce and consume the messages.

3. What do you understand by the word message?

Rationale: It’s another one of the vital spring integration interview questions for verifying the basic knowledge.

Sample Answer: Message consists of headers and payload. Headers hold the metadata information like file name, timestamp, etc. whereas payload contains the real data and can be any object type.

4. State the different types of message endpoints?

Rationale: One of the common spring boot questions is to check the conceptual knowledge of the candidate.

Sample Answer: The different types of message endpoints are message filter, message transformer, splitter, message router, aggregator, channel adapter, and service activator.

5. Define message transformer?

Rationale: Helps to check the knowledge of the candidate on the intricate details of spring integration.

Sample Answer: Message transformer is a component of spring integration that mainly adds, modifies, and removes message headers. It also transforms message payload from a particular format to another.

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Top 5 Spring security interview questions

Here is a list of the 5 best Spring security interview questions,

1. What do you understand by spring security?

Rationale: One of the basic spring security interview questions to check the fundamental knowledge of the candidate.

Sample Answer: Spring security is a framework that helps to control access and authentication. It helps to secure all spring applications.

2. Describe Open Authorization?

Rationale: Helps in verifying the detailed knowledge of the security components; one of the mandatory spring boot interview questions.

Sample Answer: Open Authorization or OAuth is the method to publish and interact with the data that is protected. It is used for authentication and authorization.

3. Define JWT?

Rationale: One of the crucial spring JPA interview questions to check the conceptual knowledge of the candidate.

Sample Answer: JWT or JSON Web Token is used for authentication in a spring boot application. It is used for securing REST API and is an open standard framework.

4. What do we need AuthenticationHandler class?

Rationale: One of the spring security interview questions that help to check the hands-on knowledge of the candidate.

Sample Answer: AuthenticationHandler Class is used in the code to re-direct different users to different pages. The logic is decided based on the roles of the users.

5.     State the difference between ROLE_ANONYMOUS and ROLE_USER?

Rationale: Aids in verifying the experience of the candidate in using various coding syntaxes.

Sample Answer: ROLE_ANONYMOUS is the role assigned by default to a user. Whereas ROLE_USER is valid only when roles are assigned to a user.