Spring Tutorial

What is Spring Framework?

Spring framework is an open source Java platform that provides comprehensive infrastructure support for developing robust Java applications very easily and very rapidly. Spring framework was initially written by Rod Johnson and was first released under the Apache 2.0 license in June 2003.

Why to Learn Spring?

Spring is the most popular application development framework for enterprise Java. Millions of developers around the world use Spring Framework to create high performing, easily testable, and reusable code.

Spring framework is an open source Java platform. It was initially written by Rod Johnson and was first released under the Apache 2.0 license in June 2003.

Spring is lightweight when it comes to size and transparency. The basic version of Spring framework is around 2MB.

The core features of the Spring Framework can be used in developing any Java application, but there are extensions for building web applications on top of the Java EE platform. Spring framework targets to make J2EE development easier to use and promotes good programming practices by enabling a POJO-based programming model.

This Spring tutorial is based on the latest Spring 7.0.0-M9 version.

Applications of Spring

Following is the list of few of the great benefits of using Spring Framework −

• POJO Based - Spring enables developers to develop enterprise-class applications using POJOs. The benefit of using only POJOs is that you do not need an EJB container product such as an application server but you have the option of using only a robust servlet container such as Tomcat or some commercial product.

• Modular - Spring is organized in a modular fashion. Even though the number of packages and classes are substantial, you have to worry only about the ones you need and ignore the rest.

• Integration with existing frameworks - Spring does not reinvent the wheel, instead it truly makes use of some of the existing technologies like several ORM frameworks, logging frameworks, JEE, Quartz and JDK timers, and other view technologies.

• Testablity - Testing an application written with Spring is simple because environment-dependent code is moved into this framework. Furthermore, by using JavaBeanstyle POJOs, it becomes easier to use dependency injection for injecting test data.

• Web MVC - Spring's web framework is a well-designed web MVC framework, which provides a great alternative to web frameworks such as Struts or other over-engineered or less popular web frameworks.

• Central Exception Handling - Spring provides a convenient API to translate technology-specific exceptions (thrown by JDBC, Hibernate, or JDO, for example) into consistent, unchecked exceptions.

• Lightweight - Lightweight IoC containers tend to be lightweight, especially when compared to EJB containers, for example. This is beneficial for developing and deploying applications on computers with limited memory and CPU resources.

• Transaction management - Spring provides a consistent transaction management interface that can scale down to a local transaction (using a single database, for example) and scale up to global transactions (using JTA, for example).

Who Should Learn Spring?

This tutorial is tailored for readers who aim to understand and utilize Spring framework for development using Java programming language. In this tutorial, we'll cover all the ways of using Spring which helps in solving the common problems developers/users face during java based development.

Prerequisites to Learn Spring?

To maximize the benefits of this tutorial, readers should have a basic understanding of Java programming. Knowledge of I/O Operations, File handling will enhance comprehension. A basic understanding of Eclipse IDE is also required because all the examples have been compiled using Eclipse IDE.

Spring Online Quizzes

This Spring tutorial helps you prepare for technical interviews and certification exams. We have provided various quizzes and assignments to check your learning level. Given quizzes have multiple choice type of questions and their answers with short explanation.

Following is a sample quiz, try to attempt any of the given answers:

Start your online quiz Start Spring Quiz.

Spring Jobs and Opportunities

Spring professionals are very much in high demand. Almost every major company is recruiting IT professionals having good experience with Spring based development.

Average annual salary for a Spring professional is around $150,000. Though it can vary depending on the location. Following are the great companies who keep recruiting Spring professionals like Spring Generative AI designers, Spring Cloud developer, Spring Batch Testers, Spring Data Scientist, ETL Developer, Spring Web Development Expert etc:

• Google
• Amazon
• Netflix
• Infosys
• TCS
• Tech Mahindra
• Wipro
• Pinterest
• Uber
• Trello
• Many more...

So, you could be the next potential employee for any of these major companies. We have developed a great learning material for Spring which will help you prepare for the technical interviews and certification exams based on Spring. So, start learning Spring using our simple and effective tutorial anywhere and anytime absolutely at your pace.

Frequently Asked Questions about Spring

There are some very Frequently Asked Questions(FAQ) about Spring, this section tries to answer them briefly.

What is Spring?

Spring is an open source development framework for enterprise Java. The core features of the Spring Framework can be used in developing any Java application, but there are extensions for building web applications on top of the Java EE platform. Spring framework targets to make J2EE development easier to use and promote good programming practice by enabling a POJO-based programming model.

What are benefits of using spring?

Following is the list of few of the great benefits of using Spring Framework:

• Lightweight − Spring is lightweight when it comes to size and transparency. The basic version of spring framework is around 2MB.

• Inversion of control (IOC) − Loose coupling is achieved in spring using the technique Inversion of Control. The objects give their dependencies instead of creating or looking for dependent objects.

• Aspect oriented (AOP) − Spring supports Aspect oriented programming and enables cohesive development by separating application business logic from system services.

• Container − Spring contains and manages the life cycle and configuration of application objects.

• MVC Framework − Spring's web framework is a well-designed web MVC framework, which provides a great alternative to web frameworks such as Struts or other over engineered or less popular web frameworks.

• Transaction Management − Spring provides a consistent transaction management interface that can scale down to a local transaction (using a single database, for example) and scale up to global transactions (using JTA, for example).

• Exception Handling − Spring provides a convenient API to translate technology-specific exceptions (thrown by JDBC, Hibernate, or JDO, for example) into consistent, unchecked exceptions.

What are the different modules in Spring framework?

Following are the modules of the Spring framework:

• Core module
• Bean module
• Context module
• Expression Language module
• JDBC module
• ORM module
• OXM module
• Java Messaging Service(JMS) module
• Transaction module
• Web module
• Web-Servlet module
• Web-Struts module
• Web-Portlet module

What is Spring configuration file?

Spring configuration file is an XML file. This file contains the classes information and describes how these classes are configured and introduced to each other.

What is Dependency Injection?

Inversion of Control (IoC) is a general concept, and it can be expressed in many different ways and Dependency Injection is merely one concrete example of Inversion of Control.

This concept says that you do not create your objects but describe how they should be created. You don't directly connect your components and services together in code but describe which services are needed by which components in a configuration file. A container (the IOC container) is then responsible for hooking it all up.

What are the different types of IoC (dependency injection)?

Types of IoC are −

• Constructor-based dependency injection − Constructor-based DI is accomplished when the container invokes a class constructor with a number of arguments, each representing a dependency on other class.

• Setter-based dependency injection − Setter-based DI is accomplished by the container calling setter methods on your beans after invoking a no-argument constructor or no-argument static factory method to instantiate your bean.

Which DI would you suggest Constructor-based or setter-based DI?

Since you can mix both, Constructor- and Setter-based DI, it is a good rule of thumb to use constructor arguments for mandatory dependencies and setters for optional dependencies. Note that the use of a @Required annotation on a setter can be used to make setters required dependencies.

What are the benefits of IOC?

The main benefits of IOC or dependency injection are −

• It minimizes the amount of code in your application.

• It makes your application easy to test as it doesn't require any singletons or JNDI lookup mechanisms in your unit test cases.

• Loose coupling is promoted with minimal effort and least intrusive mechanism.

• IOC containers support eager instantiation and lazy loading of services.