Introduction To Spring Framework - Quick Tutorial For Beginners

Image Image

In this article, we look to get an introduction to what the Spring framework is, and why it is so widely used.

You will learn

  • What is Spring Framework?
  • What are the important problems that Spring Framework solves?
  • How does Spring Framework make building enterprise applications easier?
  • What are important features of Spring Framework?
  • What are important concepts to understand in Spring Framework?
  • Why Is The Spring Framework Important?
  • What are the best practices in using Spring Framework?
  • What are Spring Projects?
  • What are Spring Modules?

Free Courses - Learn in 10 Steps

Spring Framework

This is the first article in a series of articles on Spring Framework:

What Is Spring?

Here’s the description from the Spring web site:

The Spring framework provides comprehensive infrastructural support to develop Java applications. Spring handles the infrastructure, so you can develop your application.

What does this mean?

Let’s look at some of the important features of Spring framework with examples.

Writing Loosely Coupled Code

When we write application code, we don’t want it to be tightly coupled.

What Is Tight Coupling?

Tightly coupled code could look like the following:

	public class ComplexAlgorithmImpl {
		BubbleSortAlgorithm bubbleSortAlgorithm = new BubbleSortAlgorithm();

ComplexAlgorithmImpl is tightly coupled to the BubbleSortAlgorithm.

If you need to change the sort algorithm from BubbleSortAlgorithm to QuickSortAlgorithm, then the code of ComplexAlgorithmImpl needs to change as well.

What Is Loose Coupling?

Is there a better way to manage change, than what we see over here? turns out there is - use an interface named SortAlgorithm:

	public interface SortAlgorithm {
		public int[] sort(int[] numbers);

	public class BubbleSortAlgorithm implements SortAlgorithm {

	public class QuickSortAlgorithm implements SortAlgorithm {

	public class ComplexAlgorithmImpl {
		private SortAlgorithm sortAlgorithm;

ComplexAlgorithmImpl is no longer tightly coupled to any particular sort algorithm.

Whenever you need to instantiate a ComplexAlgorithmImpl, this is how you proceed:

	ComplexAlgorithmImpl binarySearch = new ComplexAlgorithmImpl(new QuickSortAlgorithm());

The exact sort algorithm to be used can be passed as an input parameter to the constructor.

What does the Spring Framework do?

Where does the Spring framework come into the picture?

Look at the snippet below:

	public class ComplexAlgorithmImpl {
		private SortAlgorithm sortAlgorithm;

	public class QuickSortAlgorithm implements SortAlgorithm {

We defined the components and identified their dependencies by using Spring specific annotations.

We are defining ComplexAlgorithmImpl as a spring bean, and SortAlgorithm as a dependency. We are also providing an implementation of SortAlgorithm - QuickSortAlgorithm as a spring bean.

When Spring Framework looks at this code, it create a QuickSortAlgorithm bean and injects it into ComplexAlgorithmImpl bean. This is called Dependency Injection.

Advantages Of Loose Coupling

If you want to switch to a new SortAlgorithm implementation, then loose coupling makes it very easy to make the change. The code inside ComplexAlgorithmImpl does not need to change at all.

You need to remove the @Component annotation from QuickSortAlgorithm and place it at the definition of the new implementation.

The other thing you are now able to do is write a unit test for ComplexAlgorithmImpl, without worrying about the sort logic.

You can create a stub algorithm that implements SortAlgorithm, and use that in tests for ComplexAlgorithmImpl. The test would now focus on the business logic of the component, not its dependencies.

Another Example Of Loose Coupling

Have a look at the following code:

	public class WelcomeController {
		private WelcomeService service = new WelcomeService();
		public String welcome() {
			return service.retrieveWelcomeMessage();

The WelcomeController is directly creating an instance of the WelcomeService, and so it is tightly coupled to it.

If you were to use the Spring framework to decouple the two, you do something like:

	public class WelcomeService {

	public class Welcome Controller {
		WelcomeService service;

		public String welcome() {
			return service.retrieveWelcomeMessage();

Now, Spring auto-wires in the WelcomeService dependency to the WelcomeController component. When writing a unit test for this component, we can use a WelcomeService stub instead of an actual dependency.

Solving Other Problems Using Spring

The Spring framework can be used to solve a host of other problems in Java applications. Let’s look at a few of them.

Reducing Duplication In Code

Spring provides a whole range of modules such as:

  • SpringMVC
  • SpringJDBC
  • SpringORM
  • SpringAOP
  • SpringJMS
  • SpringTest

All these frameworks make it easy to write your Java code. They bring in a set of abstractions, that reduce boilerplate code.

Improving Integration With Other Frameworks

Spring does not try to provide solutions for problems that have already been solved. It provides excellent integration with frameworks such as

  • Hibernate for ORM
  • iBatis for object mapping
  • JUnit and Mockito for unit testing

What Does The Spring Framework Do?

The Spring framework facilitates the following:

  • Allows the programmers to focus on the business logic. The key feature is dependency management, and it provides excellent interfacing with external frameworks, by adding layers on top of them.
  • Enables testability, as it enables us to write decoupled code.
  • Allows for inversion of control, through dependency injection. A component is no longer tied to specific dependencies. Instead, the dependency is injected in from outside, during instantiation of the component. The Spring framework takes care of the actual injection.

Best Practices With Spring

Use Spring Initializr

Spring Initializr is a Spring project generation tool. Visit the following website -

image info

You only need to provide the Group Id, the Artifact Id, and the framework dependencies of the project. After that, you can generate the project and get started with Spring.

Consider Spring Boot

Spring Boot makes it very easy to use the Spring framework.

Write Unit Tests

Always make sure you write great unit tests, because Spring makes it easy for you.

Challenges With Spring Framework

Spring is difficult for a starting programmer to understand. However, once you understand it, you cannot stop using it!

Understand Spring Modules

Modules in Spring offer specialized functionality which can be used within a Spring application. Popular ones are:

  • SpringMVC
  • SpringJDBC
  • SpringORM
  • SpringAOP
  • SpringJMS
  • SpringTest

Explore Spring Projects

There are a wide variety of projects that have been done, under the umbrella of the Spring Framework. Popular ones include Spring Cloud, and Spring Web Services.

Do check out our video on the same topic: image info


In this article, we had an introductory look at the Spring Framework. We saw that Spring is a Java framework that makes life easy for a programmer. Spring improves the testability of the application code, and also makes it easy to interface it with external frameworks. Spring comes with its own umbrella of projects, and a rich set of modules as well.

Best Selling Udemy Courses

Image Image Image Image Image Image Image Image Image Image Image Image

Join 450,000 Learners and 30+ Amazing Courses

350,000 Learners are learning everyday with our Best Selling Courses : Spring Boot Microservices, Spring, Spring Boot, Web Services, Hibernate, Full Stack React, Full Stack Angular, Python, Spring Interview Guide, Java Interview, Java Functional Programming, AWS, Docker, Kubernetes, PCF, AWS Fargate and Azure

Do not know where to start your learning journey? Check out our amazing learning paths:
Learning Path 01 - Spring and Spring Boot Web Applications and API Developer,
Learning Path 02 - Full Stack Developer with Spring Boot, React & Angular,
Learning Path 03 - Cloud Microservices Developer with Docker and Kubernetes,
Learning Path 04 - Learn Cloud with Spring Boot, AWS, Azure and PCF and
Learning Path 05 - Learn AWS with Microservices, Docker and Kubernetes



Related Posts

Understanding jwt token

Let us understand the json web tokens

Single sign-on workflow

Let us understand the single sign-on workflow

Oauth2.0 - Resource Owner Password Credentials grant workflow

Let us understand the Oauth2.0 Resource Owner Password Credentials grant workflow

Oauth2.0 - Implicit grant workflow

Let us understand the Oauth2.0 implicit grant workflow

Oauth2.0 - Client Credentials grant workflow

Let us understand the Oauth2.0 client credentials grant workflow

Oauth2.0 - Authorization grant workflow

Let us understand the Oauth2.0 authorization grant workflow

Writing Integration Tests for Rest Services with Spring Boot

Setting up a basic REST Service with Spring Boot is a cake walk. We will go one step further and add great integration tests!

Integrating Spring Boot and Spring JDBC with H2 and Starter JDBC

Learn using Spring Boot Starter JDBC to connect Spring Boot to H2 (in memory database) using Spring JDBC. You will create a simple project with Spring Boot. You will add code to the project to connect to a database using Spring JDBC. You will learn to implement the basic CRUD methods.

JUnit Tutorial for Beginners in 5 Steps

JUnit Tutorial for Beginners in 5 Steps. Setting up a basic JUnit example and understanding the basics of junit.

JPA and Hibernate Tutorial For Beginners - 10 Steps with Spring Boot and H2

JPA and Hibernate in 10 Steps with H2 - Setting up a basic project example with Spring Boot and in memory database H2. Its a cake walk.