1. What is Spring Boot?
Spring Boot is a popular open-source framework for building and deploying production-ready, standalone, and web-based applications in the Java ecosystem. It is built on top of the Spring framework and provides an opinionated approach to configuring various components of the Spring framework and other third-party libraries.
Spring Boot aims to simplify the development process by providing a set of pre-configured templates, starters, and other tools that enable developers to create production-grade applications quickly and easily. It also includes an embedded web server, which makes it easy to deploy applications as standalone executables without the need for an external web server.
2. What is Bean?
In Spring Boot, a bean refers to an object that is managed by the Spring IoC container. The IoC (Inversion of Control) container is responsible for creating, managing, and wiring the beans in a Spring application.
Beans in Spring Boot are typically Java objects that are instantiated and managed by the Spring container. They can represent any kind of object, such as a database connection, a service object, or a user interface component.
To define a bean in Spring Boot, you can use the @Bean annotation in your Java code. This tells the Spring container that a bean of a certain type should be created and managed by the container.
Spring Boot also supports several annotations that can be used to define beans, including @Component, @Service, and @Repository. These annotations provide a convenient way to define beans without having to manually configure them in a Spring configuration file.
Overall, beans in Spring Boot play a crucial role in defining the application’s architecture and dependencies, as well as providing a mechanism for dependency injection and loose coupling.
3. What is the Spring Boot IoC container?
Spring Boot is an extension of the Spring framework that simplifies the process of creating and deploying Spring-based applications. The IOC (Inversion of Control) container used in Spring Boot is essentially the same as the one used in Spring, with some additional features and configurations to make it easier to use.
Spring Boot’s IOC container is responsible for managing the beans (objects) in a Spring Boot application, just like the Spring IOC container. It automates the process of bean configuration and dependency injection, so you don’t have to manually wire up your beans.
One of the key features of Spring Boot’s IOC container is that it provides auto-configuration. This means that it automatically configures the beans based on the dependencies that are present in the application’s classpath. This makes it much easier to get a Spring Boot application up and running quickly, without having to manually configure each individual bean.
4. What are scope of beans?
In Spring Boot, the term “beans” refers to objects managed by the Spring IoC (Inversion of Control) container. The scope of a bean determines the lifecycle of the bean and how many instances of the bean will be created.
There are several scopes available in Spring Boot:
Singleton – This is the default scope for a Spring Bean. Only one instance of the bean will be created and shared by all callers.
Prototype – A new instance of the bean will be created each time the bean is requested.
Request – A new instance of the bean will be created for each HTTP request.
Session – A new instance of the bean will be created for each HTTP session.
Global Session – This scope is used only in a Portlet context. A single instance of the bean will be created for each global Portlet session.
Application – A single instance of the bean will be created for each ServletContext.
Web Socket – A single instance of the bean will be created for each WebSocket session.
Choosing the appropriate scope for your beans is important in order to ensure that they are created and managed correctly. By default, Spring Boot beans are singleton scoped, but you can change the scope by adding the appropriate annotation to the bean class or method.
