What Is The Main Class In Spring Boot?

What does run method do in spring boot?

When Spring Boot finds a CommandLineRunner bean in the application context, it will call its run() method after the application has started up and pass in the command-line arguments with which the application has been started..

How do you call a Java class in spring boot?

In order to execute method or classes when a Spring Boot application is started you can implement the CommandLineRunner interface, which basically provides just one method: public void run(String… args) that will get called by Spring Boot only once after the application has started.

How do you test the main class of a spring boot application?

First workaround : make your Spring Boot application class with no bean declared inside. If you have them, move them in a configuration class (for make them still cover by unit test). And then ignore your Spring Boot application class in the test coverage configuration.

Is spring boot hard to learn?

It is not that hard to learn Spring Framework. It happens with all the new topic/subject, you take some time to understand its basics and concepts. … The core principal of spring framework is Inversion of Control/Dependency Inject.

Can we have two main class in spring boot?

Spring Boot allows us to define the Main class in the configuration when we have multiple main classes declared in the application. As we are using a MAVEN build, we have to configure the POM. xml for Spring Boot to identify the main class of the application.

Can we run spring boot without main method?

You don’t need the main method, all you need is to do is to extend SpringBootServletInitializer as Kryger mentioned. @SpringBootApplication public class Application extends SpringBootServletInitializer { @Override protected SpringApplicationBuilder configure(SpringApplicationBuilder application) { return application.

How do you write test cases in spring boot?

Now, you can write a Unit Test case for Order Service under the src/test/resources package. The complete code for build configuration file is given below. You can create an executable JAR file, and run the Spring Boot application by using the following Maven or Gradle1 commands.

What do you learn in spring boot?

You will explore different Spring Boot features along the way, like starter POMs, which allow you to just declare one starter package instead of several individual libraries. You will also learn how to develop a modern Java web application using Spring Boot, a RESTful web service, and integrating a JavaScript-based UI.

Why do we need main method in spring boot?

Why am I creating a class with the main method? that’s how Spring Boot creates a standalone Spring Application. It doesn’t need a servlet container. It doesn’t need to be deployed on a server. … So we want to set up a simple application and start the servlet container and host that application in that servlet container.

Is spring boot easy?

Spring Boot is an open source Java-based framework used to create a Micro Service. It is developed by Pivotal Team. It is easy to create a stand-alone and production ready spring applications using Spring Boot.

What is @EnableAutoConfiguration in spring?

Annotation Type EnableAutoConfiguration Enable auto-configuration of the Spring Application Context, attempting to guess and configure beans that you are likely to need. Auto-configuration classes are usually applied based on your classpath and what beans you have defined. For example, if you have tomcat-embedded.

How do you call a method in spring boot?

Run method on application startup in Spring BootUsing @Postconstruct method in singleton bean.Using ApplicationEvent — ApplicationReadyEvent or ContextRefreshEvent.Using CommandLineRunner.Using ApplicationRunner.