Spring is a Java framework that uses a container to build and manage the various components of an application. The container (often called the Spring application context) connects the various components in the application using the Dependency Injection (DI) design pattern. DI allows you to use an object in a dependent class without creating a new instance of it from the dependent class.
So, instead of allowing each component to create new instances of the ones it relies on, Spring’s container creates and maintains an instance of each component it hosts. This container then injects an instance of a component into all other components that need it.
Discover the main features of Spring
The Spring Framework consists of about 20 well-organized modules that play an integral role in the ability to build and manage applications. Based on the primary characteristics of these modules, you can group them into five categories.
Spring uses a container to create and manage the various components (which it calls beans) of an application. The container is accessed through Spring’s ApplicationContext interface, which allows you to instantiate, configure, and assemble objects (or beans). With the help of configuration metadata, Spring’s container can do its work.
This configuration metadata can take many different forms, but the typical form is XML. In addition to beans, Spring’s container also consists of core, context, and expression modules.
Spring Data Access/Integration
The data access/integration aspect of the Spring Framework consists of several submodules: JDBC, ORM, OXM, JMS, and Transactions. These modules work together to manage any data used by your application.
The Web feature of Spring Applications provides web-oriented integration for your applications. In addition to web-oriented integration, Spring also provides a web servlet module. The web servlet module is responsible for Spring’s model–view–controller (MVC) implementation.
Spring Aspect-Oriented Programming (AOP)
Spring’s AOP framework is one of its core components. Although the AOP framework is not critical to Spring’s container functionality, it complements the container by being a capable middleware solution. One of the key features of an AOP framework is that it provides declarative enterprise services for your application, namely declarative transaction management.
Declarative transaction management is a desirable approach to software development because it has minimal impact on application code.
Spring places significant importance on application testing. Its testing module supports integration testing and unit testing using JUnit or TestNG.
As you can see from the image above, you have to make several decisions. The first is the type of project you want to start. Spring offers three options: Gradle for Groovy, Gradle for Kotlin, or Maven. This sample application will use a Maven project.
Other options you can choose from are the language (Java), the version of Spring Boot you want to use, and project metadata. Spring’s five areas already have some dummy data to help you build a sample application.
However, you will need to update these fields with project-specific data, as this metadata will describe your Spring application, including Spring beans and their methods.
Next, you need to select the packaging in which you want to keep your files (JAR or WAR). You can then select the version of Java you have on your device. The final decision you will need to make is the type of dependencies for your application.
Spring provides a number of dependencies that you can use to add properties to your application. To add a new dependency to your application, simply click on the Add Dependencies button to the right of the Spring initializer.
For this sample application, all you need is Spring Web. This dependency allows you to build web applications using the MVC architecture. After you have selected all the dependencies you want to use in your application, one click generate. This will download the project boilerplate for you.
Now you have a Spring Boot (which is one of Spring’s libraries) project. The last step is to import the project into your preferred IDE.