Spring Boot comes with over 40 different starter modules, which provide ready-to-use integration libraries for many different frameworks, such as database connections that are both relational and NoSQL, web services, social network integration, monitoring libraries, logging, template rendering, and the list just keeps going on. While it is not practically feasible to cover every single one of these components, we will go over the important and popular ones to get an idea of the possibilities and the ease of application development that Spring Boot provides us with.

We will start by creating a basic simple project skeleton, and Spring Boot will help us achieve this:

1. Head over to http://start.spring.io
2. Fill out a simple form with the details about our project
3. Click on Generate Project alt + a premade project skeleton will download; this is where we begin

You will see the Project Dependencies section, where we can choose the kind of functionalities that our application will perform: Will it connect to a database? Will it have a web interface? Do we plan to integrate with any of the social networks bake in operational support? and so on. By selecting the desired technologies, the appropriate starter libraries will be added automatically to the dependency list of our pregenerated project template.

Before we proceed with the generation of our project, let's go over what exactly a Spring Boot starter is and the benefits it provides us with.

Spring Boot aims to make it easy to get started with creating an application. Spring Boot starters are bootstrap libraries that contain a collection of all the relevant transitive dependencies that are needed to start a particular functionality. Each starter has a special file, which contains the list of all the provided dependencies Spring provides. Let's take a look at the following link for a spring-boot-starter-test definition as an example:

https://github.com/spring-projects/spring-boot/blob/master/spring-boot-project/spring-boot-starters/spring-boot-starter-test/src/main/resources/META-INF/spring.provides

Here we will see the following code:

provides: spring-test, spring-boot, junit, mockito, hamcrest-library, jsonassert, json-path 

This tells us that by including spring-boot-starter-test in our build as a dependency, we will automatically get spring-test, spring-boot, junit, mockito, hamcrest-library,jsonassert, and json-path. These libraries will provide us with all the necessary things in order to start writing application tests for the software that we will develop, without needing to manually add these dependencies to the build file individually.

With more than 100 starters provided, and with the ongoing community additions increasing the list, it is very likely that unless, we find ourselves with the need to integrate with a fairly common or popular framework, there is already a starter out there that we can use.

The following table shows you the most notable ones so as to give you an idea of what is available: