Spring Boot Interview Questions- Part 1

Part 1  | Part 2 | Part 3

Spring interview questions and answer

Nowadays many interview has a set of questions on Spring when it comes to advanced Java Interviews. Here are frequently asked Spring Boot Interview questions with answers.

  • What is Spring Boot?

Spring Boot makes it easy to create stand-alone, production-grade Spring based Applications that you can “just run”.
You can use Spring Boot to create Java applications that can be started using java -jar or more traditional war deployments.

  • What are the advantages of spring boot application?

Provide a range of non-functional features that are common to large classes of projects (e.g. embedded servers, security, metrics, health checks, externalized configuration).
Opinionated view of the Spring platform and third-party libraries so you can get started with minimum fuss.
Absolutely no code generation and no requirement for XML configuration.
Provide a radically faster and widely accessible getting started experience for all Spring development.

  • What are the requirements of Spring boot System?

Spring Boot 1.5.9.RELEASE requires
Java 7 +
Spring 4.3.13 +

For build support
Maven 3.2+
Gradle 2.9+

Container Support
Tomcat 7+
Jetty 8+ (Jetty 9.3 requires JDK 8 +)

Read more Spring boot system requirements

What is the latest version of spring boot and its System requirement?

As per July 2018 Spring boot latest version is 2.1.

Spring boot needs Java 8+ version and Spring 5 framework as minimum version.

Gradle 4 + version

  • Spring boot 2 new features?

Refer : Spring boot 2 new features

  • What are the use of @EnableAutoConfiguration annotation?

This annotation tells Spring Boot to “guess” how you will want to configure Spring, based on the jar dependencies that you have added.

Read more @enableautoconfiguration spring boot example

  • What is Spring Boot Starter?

Spring Boot provides a number of “Starters” that make easy to manage dependencies for your project.

Read More Spring boot starter

  • What is spring-boot-starter-parent?

The spring-boot-starter-parent is a special starter that makes Maven or Gradle dependency-management easier by adding jars to your classpath.

Read More spring-boot-starter-parent

  • What is spring-boot-starter-web?

This starter will add Tomcat and Spring MVC dependency to our application and its default configuration.

Read More spring-boot-starter-web

  • How to create an executable jar using spring boot?

Add this below plugin to pom.xml

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

Use mvn clean package to create executable jar file

Read More spring boot executable jar example

  • How do you run and stop spring boot executable jar?

Open cmd or shell window and use java -jar as shown below

$ java -jar myproject-0.0.1-SNAPSHOT.jar

To stop use ctrl+C

Read More run spring boot jar from command line

  • How do you change JDK version in spring boot?

Java 1.6 as the default compiler level.
You can overwrite it by adding java.version property tag as shown below

<properties>
    <java.version>1.8</java.version>
</properties>
  • What is the use of @SpringBootApplication annotation?

The @SpringBootApplication annotation is equivalent to using @Configuration, @EnableAutoConfiguration and @ComponentScan with their default attributes

Since many spring Boot developers have their main class annotated with @Configuration, @EnableAutoConfiguration and @ComponentScan, spring boot provides you a new annotation @SpringBootApplication as replacement.

  • What is spring-boot-devtools ?

Applications that use spring-boot-devtools will automatically restart whenever files on the classpath change. This can be a useful feature when working in an IDE as it gives a very fast feedback loop for code changes.

  • What are Profiles in spring boot?

Spring Profiles provide a way to segregate parts of your application configuration and make it only available in certain environments. Any @Component or @Configuration can be marked with @Profile to limit when it is loaded

  • Spring Boot Actuator?

Spring Boot Actuator help you monitor and manage your application health when you push it to production.
You can choose to manage and monitor your application by using HTTP endpoints.

  • How do you Change tomcat or jetty HTTP port?

You can change the tomcat http port by changing default http property in application.properties file.

  • How to disable specific auto-configuration in spring boot?

You can use exclude property as shown below to disable specific auto configuration

@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})

 

Spring boot interview questions- Part 1
Spring boot interview questions- Part 2
Spring boot interview questions- Part 3

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