Spring is the most used Java Enterprise Edition (Java EE) framework for enterprise Java. Majority of developers around the world use Spring Framework to create high performing, testable, and reusable code. Spring framework is an open-source Java platform originally written by Rod Johnson and released under the Apache 2.0 license in June of 2003 to provide infrastructure support for developing Java applications. It is highly lightweight when it comes to size and transparency. The basic version of the Spring framework is closer to 2MB. It is one of the most popular Java Enterprise Edition frameworks, it helps developers create high performing and Scalable J2ee web applications using plain old Java objects (POJOs).
A Java framework is a vast body of predefined code to which developers can add codes to solve a problem in a particular domain. There are a lot of Java frameworks such as Java Server Faces (JSF), Maven, Hibernate, Struts, and Spring. Spring framework comes on top as it aims to make J2EE enterprise application development easier to use and promotes best programming practices by enabling a POJO-based programming model. The core features of the Spring architecture is used for developing any Java project, it enhances the way that developers write and deliver infrastructure code in Java applications.
Basic Concepts of Spring
Inversion of control
The term IOC (Inversion of control) has its function in its name - it inverts the usual hierarchy of control for meeting object relationships. Instead of depending on application code to define how objects relate to each other, relationships are defined by the framework. IOC introduces consistency and predictability to object relations, but it does require the developer to give up some fine-tuned control. In this concept, objects do not depend on the other objects but have information about their abstractions for further communication.
Dependency Injection
It is a composition of structural design patterns, in which for each function of the application there is one conditionally independent object that can demand to use other objects known to it by interfaces. Dependencies are applied to the service at the time of its creation. It is a situation where we add an element of one class into another. One independent object uses other objects with the help of interfaces in this concept. DI is transferred at the time of creation. It can either be applied with the help of setters or passing parameters in the constructor. While usage, DI is implemented by passing parameters to the constructor or using setters. Libraries that perform this approach are also called IoC containers. Read More- Why Spring Framework is Preferred Choice for Java Enterprise Apps?
