Spring Core

Question 1

DI

Answer 1

Dependency Inversion: A design pattern that provides for loose coupling; it uses service components, consumer classes, and injector classes.

Question 2

Service components

Answer 2

interface/abstract class that define a contract for services

Question 3

Consumer class

Answer 3

written in terms of service interface

Question 4

What is Spring?

Answer 4

Spring is an open-source framework that sits on top of Java; series of JAR files (dependencies to add to Maven); provides an abstract layer to some of more complex parts of Java; Spring helps structure whole applications in a consistent, productive manner, encouraging SOLID design

Question 5

What are the benefits of Spring?

Answer 5

Lightweight - about 2 MB; IoC (Inversion of Control) - loose coupling; Spring Container: Spring contains and manages lifecycle of objects; Boilerplate code - Spring provides templates which allow you to reduce amount of boilerplate code.

Question 6

Spring Core Container

Answer 6

Spring container is the core of Spring Framework, responsible for creating and configuring the objects needed for an application, managing complete lifecycle for creation/destruction of objects; uses DI to wire objects together; these objects are called Spring Beans

Question 7

ApplicationContext

Answer 7

Interface used to represent the Spring IoC container and therefore load up the configuration

Question 8

@Component Annotation

Answer 8

@Component tells Spring: “Create an instance of this class and manage it as a bean in the ApplicationContext.”

Question 9

@Autowired Annotation

Answer 9

@Autowired tells Spring: “Inject a bean of the required type here.” Spring looks in the ApplicationContext, finds a matching bean, and injects it.

Question 10

IoC

Answer 10

Inversion of Control: It is responsible for creating, managing, and configuring application objects (beans). Using Dependency Injection:

Automatically injects required dependencies into beans.
Manages bean creation, initialization, and destruction.
Supports XML, annotation-based, and Java-based configuration.
Separates object creation from business logic, making applications more flexible and testable.