Spring Boot Interview Questions For 10 Years Experienced

What Is Java Runtime Environment

JRE in Java is simply an environment that allows developers or programmers to run Java-based apps on operating systems. You can say that it facilitates the interaction between OS and the program.

Java JRE provides several resources to programmers, such as libraries, JVM, Java Plug-in, Web Start, etc. It is available to download on Windows, Linux, macOS, and Oracle Solaris.

How To Create A Login Page In Spring Boot

You can create a simple and default login page in spring boot, you can make use of Spring security. Spring security secures all HTTP endpoints where the user has to login into the default HTTP form provided by spring.

We need to add spring-boot-starter-security dependency in your pom.xml or build.gradle and a default username and password can be generated with which you can log in.

What Does Spring Boot Mean

Spring Boot is a system from “The Spring Team” to facilitate the bootstrapping and development of new Spring Applications. It gives defaults to code, and annotation configurations to snappy begin new spring projects at no time. It takes after the “Opinionated Defaults Configuration” Approach to escape from a lot of standard code and configuration to enhance Development, Unit Test, and Integration Test Process.

Here are some of the various advantages of using Spring Boot:

• It is quite easy to create Spring Based applications with Java or Groovy.
• It lessens lots of improvement time and expands profitability.
• It abstains from writing lots of standard Codes, Annotations, and XML Configuration.
• It is quite easy to coordinate Spring Boot Application with its Spring Ecosystem like Spring JDBC, Spring ORM, Spring Data, Spring Security and so forth.
• It takes after the “Opinionated Defaults Configuration” Approach to diminish Developer effort
• It gives Embedded HTTP servers like Tomcat, Jetty and more to create and test our web applications effectively.
• It gives CLI tool to create and test Spring Boot Applications from commanding prompt very easily and rapidly.
• It gives lots of modules to create and test Spring Boot Applications effectively utilizing Build Tools like Maven and Gradle
• It provides loads of plug-ins to work with implanted and in-memory Databases effortlessly.

Various Spring Boot Features are as follows:

• Web Development

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Q15 What Is Graalvm Native Image Support In Spring Boot

This is the new feature introduced in Spring Boot 3.0 release. GraalVM Native Images provide a new way to deploy and run Java applications. Compared to the Java Virtual Machine, native images can run with a smaller memory footprint and with much faster startup times.

GraalVM is a high-performance JDK intended to speed up the execution of applications written in Java and other JVM languages while also offering runtimes for JavaScript, Python, and a number of other popular languages. GraalVM offers two ways to run Java applications: on the HotSpot JVM with Graal just-in-time compiler or as an ahead-of-time compiled native executable.

GraalVM Native Images are standalone executables that can be generated by processing compiled Java applications ahead-of-time. Native Images generally have a smaller memory footprint and start faster than their JVM counterparts. They are well suitable for applications that are deployed using container images. A GraalVM Native Image is a complete, platform-specific executable. We do not need to ship a Java Virtual Machine in order to run a native image.

If you want to know more about it and experiment with GraalVM you can go ahead with the official documentation on GraalVM Native Image Support.

How Can You Configure Logging In Spring Boot Application

Spring Boot comes with support for Java Util Logging, Log4J2 and Logback and it will be pre-configured as Console output.Hence,You can simply specify logging.level in application.properties.

If you want to do logging configuration explicitly, You can also create logback.xml in main/java/resources folder and specify logging configuration in the file. Spring Boot will pick this file and configure logging accordingly.

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What Is An Aspect

In computing, aspect-oriented programming is a programming paradigm that aims to increase modularity by allowing the separation of cross-cutting concerns. In simple words we can say that it is a methodology which will separate cross-cutting concerns from core concerns. For example, if writing an application for handling medical records, the indexing of such records is a core concern, while logging a history of changes to the record database or user database, or an authentication system, would be cross-cutting concerns.

Core concern: The logic that seems to be mandatory and without having that logic the existence of our application will not be there, such kind of logic is considered as core concern. Ex: writing business logic, fetching data from database/external API etc.

Cross-Cutting concern: The program logic which is common across the application and the presence/absence of that logic does not impact core business functionality but if we apply the cross-cutting logic then it affects multiple points of an application is nothing but cross-cutting logic. Ex: Logging, Caching, Transaction processing, Security etc.

The above figure represents a typical application thats broken down into modules. Each modules main concern is to provide services for its particular domain. But each module also requires similar ancillary functionalities, such as security, logging & transaction management.

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What Is The Difference Between Equals Method And Equality Operator In Java

There are a number of key differences between the equals method and the equality operator in Java. The primary difference is that one is a method, and another is an operator.

Such tricky concepts are usually asked when you have some experience in this field. So, you need to study the core Java interview questions and answers for experienced professionals really well.

For this question, we have created a tabular comparison to help you understand the differences between the equals method and equality operator in Java.

}while

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Q6 What Are The Starter Dependencies A Spring Boot Application

In Spring Boot, we highly work with starter dependencies. The Starters are the ready made small projects that we can include in our application. Officially they are called dependency descriptors. Technically, the starters contain a lot of the dependencies that we need to get a project up and running quickly and with a consistent, supported set of managed transitive dependencies. We dont have to manually search for required jars to run a project.

For example, if you want to develop a Spring Web Application, include the spring-boot-starter-web dependency in your project. However, if you are using STS as an IDE, you need to just search for Web and select Spring Web. The STS will automatically add the spring-boot-starter-web dependency in your pom.xml.

All official starters follow a similar naming convention spring-boot-starter-*, where * stands for a particular type of application. This naming structure is intended to help when you need to find a starter. As aforementioned, the Maven integration with many IDEs like STS lets you search dependencies by name. You can find the list of some commonly used starters from the link Common Starters in Spring Boot.

What Is The Difference Between Composition And Aggregation In Java

Both composition and aggregation are associations in Java. The former is considered a strong association, while the latter is considered a weak association. Lets understand the differences between them with the below tabular comparison:

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What Is The Difference Between Spring And Spring Boot

Difference between Spring and Spring boot are as follows:

Spring

Spring boot-

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26) What are the ways in which Spring Boot can read configurations?

A) Spring Boot can bind variables via @PropertySource, @Value, @Environment, @ConfigurationProperties.

27) What log framework does Spring Boot support? Which is the recommended and default log framework?

A) Spring Boot supports Java Util Logging, Log4j2, and Lockback as the logging framework. If you use the Starters launcher, Spring Boot will use Logback as the default logging framework.

28) What are the ways in which SpringBoot implements hot deployment?

A) There are two main ways:

29) How do you understand the Spring Boot configuration load order?

A) In Spring Boot, there are several ways to load a configuration.

30) How does Spring Boot define multiple sets of different environment configurations?

A) Provide multiple sets of configuration files, such as:

Applcation.properties application-dev.properties application-test.properties application-prod.properties

Specify a specific configuration file at runtime.

31) Can Spring Boot be compatible with older Spring projects? How do I do this?

A) Compatible, use @ImportResourceannotations to import old Spring project configuration file.

32) What are the methods to protect Spring Boot applications?

• Use HTTPS in production
• Check your dependencies with Snyk
• Upgrade to the latest version
• Enable CSRF protection
• Use content security policies to prevent XSS attacks

33) What are the new features of Spring Boot 2.X? What is the difference with 1.X?

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What Is A Swagger In Spring Boot

Swagger is used for clearly detailing and documenting RESTful APIs in a machine-readable and human-readable format, which is easily comprehensible for testers and developers, as well as individuals having little knowledge of source code.

Enabling hassle-free application discovery, development, and integration, Swagger allows API consumers to interact with remote services with minimum implementation logic.

How To Write Custom Log Configuration In Spring Boot

You can force Spring Boot to use a particular logging system using the org.springframework.boot.logging.LoggingSystem system property. The value should be the fully-qualified class name of a logging system implementation. You can also disable Spring Boots logging configuration entirely by using a value of none.

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What Is A Java Bean

Java Bean: A JavaBean is nothing but a POJO class but have a strict set of rules:

Example:- EmployeeBean.java

publicclassEmployeeBeanimplementsjava.io.Serializable publicEmployeeBean publicStringgetName publicvoidsetName // additional getters/setters}

What Is Garbage Collection In Java

It is an important concept that you must know while appearing for the interview. This is one of the most asked Java garbage collection interview questions.

The meaning of garbage collection in Java programming is that it automates the memory management for programs running on the Java virtual machine.

So, when you create and run programs, heaps of memory are allocated for memory consumption. In the long run, there will be several objects of the Java program that wont be required. What the garbage collection does is remove the unused objects automatically. As a result, it optimizes memory.

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2. What is the need for Spring Boot?

It is one of the most commonly asked Spring Boot Interview questions, and you can answer it by pointing out significant advantages of Spring Boot.

While Spring offers developers an ideal environment to develop large applications, the amount of configuration and its complexity makes it challenging to do so.

Here is where Spring Boot comes to rescue. Its features like pre-built templates and auto-configuration allow developers to use existing spring functionalities with more ease, minimum effort, and maximum efficiency.

The main advantages of Spring Boot are:

• It reduces development and testing time.
• It uses JavaConfig instead of XML.
• It provides an opinionated development approach.
• It offers starter projects or defaults for agile development.
• No separate web server is required hence there is no need to boot up Glassfish, Tomcat, or any other server.

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3. Can you name and briefly explain all the spring boot components/features?

With this question, the interviewer intends to gauge the theoretical knowledge of your concepts. If you have previous experience in the domain or worked on any Spring Boot projects, provide the answer with examples.

The main features of Spring Boot are

1. Starter dependency

2. Auto-Configuration

3. Spring Initializer

Spring Boot Interview Question Answer For Java Developers

1. What is Spring Boot? Why should you use it?you dont need to setup a Tomcat server2. What are some important features of using Spring Boot?1. Starter dependencyRESTful services2. Auto-Configuration3. Spring Initializer4. Spring Actuator5. Spring CLILearn Spring Boot Rapid Spring Application Development3. What is auto-configuration in Spring boot? how does it help? Why Spring Boot is called opinionated?Spring Security MasterclassLearn Spring 5 and Spring Boot 2 courses4. What is starter dependency in Spring Boot? how does it help?Spring MVCJackson5. What is the difference between @SpringBootApplication and @EnableAutoConfiguration annotation?@EnableAutoConfiguration@SpringBootApplication6. What is Spring Initializer? why should you use it?Spring Boot Masterclass.7. What is Spring Actuator? What are its advantages?beansCPU and memory usageSpring Security Certification Class8. What is Spring Boot CLI? What are its benefits?Spring Boot in Action9. Where do you define properties in Spring Boot application?10. Can you change the port of the Embedded Tomcat server in Spring boot? If Yes, How?Learn Spring Boot in 100 Steps11. What is the difference between an embedded container and a WAR?web server12. What embedded containers does Spring Boot support?13. What are some common Spring Boot annotations?Main class14. Can you name some common Spring Boot Starter POMs?15. Can you control logging with Spring Boot? How?classpath

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Which Is The Spring Boot Latest Version

The latest version of spring boot is 2.6.0. It came out with a lot of dependency upgrades, java 15 support and much more.

Yes, now as you are brushed up with spring boot interview questions and answers. We have also tried to cover all the springboot interview questions for experienced professionals. Hope you can easily crack the spring boot interview now!

Please feel free to comment below if you have any queries related to the above questions or answers. Also, do comment if you find any other questions that you think must be included in the above list of questions.

What Are Some Of The Disadvantages Of Using Spring Boot

Some of the common drawbacks of Spring Boot to keep in mind is its complexities. While working with Spring Boot, converting legacy to a full-fledged Spring Boot app could take up your time. Secondly, Spring Boots flexibility with large-scale projects isnt suitable in the long run. As a developer, if you wish to choose Spring Boot to create monolithic apps, you will be disappointed. Finally, Spring Boots lack of control could multiply dependencies that could result in the execution of massive deployment data.

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What Are The Different Modules Available In Spring

Spring Framework contains a lot of features which are well-organized in about 20 modules. These modules can be grouped together based on their primary features into Core Container, Data Access/Integration, Web, AOP, Instrumentation, Messaging, and Test, as shown in the following diagram.

Core Container: The Core Container consists of the Core, Beans, Context, Context-Support and Expression modules.

spring-core& spring-beans modules provide the fundamental parts of the framework including IoC and Dependency Injection features. We can use BeanFactory to create the IoC Container. BeanFactory is a sophisticated implementation of the factory design pattern. It removes the need for a programmatic singleton design pattern.

spring-context module builds on the solid base provided by the Core & Beans modules. Means to access objects in a framework-style manner we can use Context module which is similar to a JNDI registry. Context module inherits its features from the Beans module and adds support for internationalization, event propagation, resource loading. Context module also supports Java EE features such as EJB, JMX, and basic remoting. We can use ApplicationContext to create the IoC Container similar to BeanFactory but is more advanced than BeanFactory.

spring-context-support provides support for integrating common third-party libraries into a Spring application context for caching , mailing , scheduling and template engines .

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Can We Create A Non

Yes, but the application could also be called as spring boot standalone application.

To create a non-web application, your application needs to implement CommandLineRunner interface and its Run method for the running of our application. So this run method always acts like the main of our non-web application.

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What Is The Easiest Way To Deploy A Spring Boot Application In Production What Other Options Are There

The simplest way to deploy your Spring Boot application is as a .jar file with an embedded servlet container, to any server or platform that has a JRE installed. For organizational and historical reasons, you can also deploy your Spring Boot application as a .war file, into an existing servlet container or application server.

Last but not least, you can, of course, also put your .jar file into a Docker image and even deploy those with Kubernetes.

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