Spring Tutorial
This spring tutorial provides in-depth concepts of Spring Framework with simplified examples. It was developed by Red Johnson in 2003. Spring framework makes the easy development of JavaEE application.
Spring Framework

Spring is a lightweight framework. It can be thought of as a framework of frameworks because it provides support to various frameworks such as Struts, Hibernate, Tapestry, EJB, JSF etc. The framework, in broader sense, can be defined as a structure where we find solution of the various technical problems.

The Spring framework comprises several modules such as IOC, AOP, DAO, Context, ORM, WEB MVC etc. We will learn these modules in next page. Let’s understand the IOC and Dependency Injection first.

Inversion Of Control (IOC) and Dependency Injection

These are the design patterns that are used to remove dependency from the programming code. They make the code easier to test and maintain. Let’s understand this with the following code:

class Employee{
Address address;
Employee(){
address=new Address();
}
}

In such case, there is dependency between the Employee and Address (tight coupling). In the Inversion of Control scenario, we do this something like this:

class Employee{
Address address;
Employee(Address address){
this.address=address;
}
}

Thus, IOC makes the code loosely coupled. In such case, there is no need to modify the code if our logic is moved to new environment.

In Spring framework, IOC container is responsible to inject the dependency. We provide metadata to the IOC container either by XML file or annotation.

Advantage of Dependency Injection

  • makes the code loosely coupled so easy to maintain
  • makes the code easy to test

Advantages of Spring Framework

There are many advantages of Spring Framework. They are as follows:

1) Lightweight: Spring framework is lightweight because of its POJO implementation. The Spring Framework doesn’t force the programmer to inherit any class or implement any interface. That is why it is said non-invasive.

2) Easy to develop JavaEE application: The Dependency Injection feature of Spring Framework and it support to various frameworks makes the easy development of JavaEE application.

3) Easy to test: The Dependency Injection makes easier to test the application. The EJB or Struts application require server to run the application but Spring framework doesn’t require server.

4) Loose Coupling: The Spring applications are loosely coupled because of dependency injection.

5) Powerful abstraction: It provides powerful abstraction to JavaEE specifications such as JMS, JDBC, JPA and JTA.

6) Declarative support: It provides declarative support for caching, validation, transactions and formatting

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