Quick Answer: What Is Init Method In Spring?

What is the difference between @configuration and @component in Spring?

@Component Indicates that an annotated class is a “component”.

Such classes are considered as candidates for auto-detection when using annotation-based configuration and classpath scanning.

A @Configuration is also a @Component, but a @Component cannot act like a @Configuration..

What is @EnableWebMvc in spring?

When you’re using Java code (as opposed to XML) to configure your Spring application, @EnableWebMvc is used to enable Spring MVC. … @EnableWebMvc is equivalent to in XML. It enables support for @Controller -annotated classes that use @RequestMapping to map incoming requests to a certain method.

What is spring life cycle?

A “Spring bean” is just a Spring managed instantiation of a Java class. The Spring IoC container is responsible for instantiating, initializing, and wiring beans. The container also manages the life cycle of beans. Spring provides several ways through which you can tap into the bean lifecycle.

What is the IoC in spring?

Spring IoC is the mechanism to achieve loose-coupling between Objects dependencies. To achieve loose coupling and dynamic binding of the objects at runtime, objects dependencies are injected by other assembler objects. … Spring IoC container provides us different ways to decouple the object dependencies.

What are the scopes in spring?

Spring – Bean ScopesSr.No.Scope & Description1singleton This scopes the bean definition to a single instance per Spring IoC container (default).2prototype This scopes a single bean definition to have any number of object instances.3 more rows

What is spring Autowiring?

Autowiring feature of spring framework enables you to inject the object dependency implicitly. It internally uses setter or constructor injection. Autowiring can’t be used to inject primitive and string values. It works with reference only.

What does spring application run do?

SpringApplication#run bootstraps a spring application as a stand-alone application from the main method. It creates an appropriate ApplicationContext instance and load beans. It also runs embedded Tomcat server in Spring web application.

When Init method is called in spring?

The init-method attribute specifies a method that is to be called on the bean immediately upon instantiation. Similarly, destroymethod specifies a method that is called just before a bean is removed from the container.

What happens when spring application starts?

Whenever we create Spring boot application using spring.io or using STS IDE we see there is main class autogenerated and somehow it do some magic when we run the spring boot application, how come the main method initiate servlet, run the container and all that actually happened when spring boot called this main method.

What is Proxymode in spring?

For those of you who are not aware of Method Injection, it allows you to inject methods instead of objects in your class. … Method Injection is useful in scenarios where you need to inject a smaller scope bean in a larger scope bean.

What is the default scope in spring?

1.1. singleton is default bean scope in spring container. It tells the container to create and manage only one instance of bean class, per container.

What is @configuration in spring?

@Configuration annotation is used for Spring annotation based configuration. The @Configuration is a marker annotation which indicates that a class declares one or more @Bean methods and may be processed by the Spring container to generate bean definitions and service requests for those beans at runtime.

What is Init method in servlet?

Init() method is called by the servlet container to indicate to a servlet that the servlet is being placed into service. The servlet container calls the init method exactly once after instantiating the servlet. The init method must complete successfully before the servlet can receive any requests.

How does Spring Data Repository Work?

Working with Spring Data Repositories. The goal of Spring Data repository abstraction is to significantly reduce the amount of boilerplate code required to implement data access layers for various persistence stores. This chapter explains the core concepts and interfaces of Spring Data repositories.

How does Spring application work?

It is the heart of the Spring Framework. The IoC container receives metadata from either an XML file, Java annotations, or Java code. The container gets its instructions on what objects to instantiate, configure, and assemble from simple Plain Old Java Objects (POJO) by reading the configuration metadata provided.

What is __ init __ in Python?

__init__ is one of the reserved methods in Python. In object oriented programming, it is known as a constructor. The __init__ method can be called when an object is created from the class, and access is required to initialize the attributes of the class.

What is encapsulation in Java?

Encapsulation in Java is a mechanism of wrapping the data (variables) and code acting on the data (methods) together as a single unit. … Declare the variables of a class as private. Provide public setter and getter methods to modify and view the variables values.

What is singleton in spring?

Singleton pattern ensures that one and only one instance of a particular class will ever be created per classloader where as the scope of a Spring singleton bean is described as ‘per container per bean’. Singleton scope in Spring means that this bean will be instantiated only once by Spring.

What is difference between IoC and DI in spring?

IOC is a concept where the flow of application is inverted. The control of the logic which is not part of that entity is taken by someone else. DI provides objects that an object needs. So rather than the dependencies construct themselves they are injected.

What is Init method in Java?

Init method is a predefined method to initialize an object after its creation. Init method is a life cycle method for servlets for java. It is started by the browser when java program is loaded and run by the browser. Init method is a predefine method to initialize an object after its creation.

What is @qualifier in spring?

The @Qualifier annotation is used to resolve the autowiring conflict, when there are multiple beans of same type. The @Qualifier annotation can be used on any class annotated with @Component or on method annotated with @Bean . This annotation can also be applied on constructor arguments or method parameters.

What does @bean do in spring?

A bean is an object that is instantiated, assembled, and otherwise managed by a Spring IoC container. These beans are created with the configuration metadata that you supply to the container.

Why it is called IoC in spring?

Inversion of Control (IoC) and Dependency Injection (DI) are used interchangeably. IoC is achieved through DI. … By DI, the responsibility of creating objects is shifted from our application code to the Spring container; this phenomenon is called IoC.

How many ways can you set up spring?

There are three ways to define configuration, available in Spring 4 by default:xml-based configuration, when you describe configuration in xml file;java-based configuration, when configuration is Java class, marked with specific annotations;groovy-based configuration, when configuration is file with Groovy code;