Having presented Thorntail's features and its relationship with Java EE/Jakarta EE and MicroProfile.io, it's time to start to build our microservices application.

We will build a simple fantasy football application that is divided into four Maven projects, as follows:

1. A microservice application that handles the football players domain; it will expose create, read, update, and delete (CRUD) API, and it will store and retrieve information using a PostgreSQL database.
2. A microservice application that handles the fantasy football player domain and the presidents of the fantasy teams; it will expose a CRUD API, and it will store and retrieve information using a MySQL database.

3. A microservice application that handles the fantasy team's domain; it will expose a CRUD API, and it will store and retrieve information using a MongoDB database.
4. A microservice application that will be the web interface through which the various APIs call, in order to sign up to the fantasy league, create the fantasy team, and buy the football players.

We have decided to use a different database in order to show you that the microservice architecture works using different languages, and to confirm the concept that a microservice must own a specific data domain.

To build our application, we will use the following tools, and for each one, we will specify the information needed to install them:

1. Apache Maven 3.5.4: Here is the link to install (https://maven.apache.org/install.html)
2. JDK 1.8.0_171: You are free to use Oracle JDK or OpenJDK, but we recommend OpenJDK (http://openjdk.java.net/install/) 
3. Thorntail 2.0.0: Here is the link to install (https://thorntail.io/)
4. Docker Community edition 18.03.1 : This is so that you can easily install and use the different databases required for our application (https://docs.docker.com/install/)
5. AngularJS: This is to build the frontend layer; we will describe the instructions to install it later on.