As of the date of this writing, this is a SPRING BOOT application. Since this is the PMDB API Services Layer, it is considered 'the' interface to the PMDB Database.
In order to work on this application, you will need to download Spring Boot STS (Spring Tool Suite) LINK. This is an Eclipse based IDE. Try the "Getting Started Guides" that are available in order to get familiar (if you are not already) with Spring Boot.
Lombok is used in this project. Lombok basically eliminates a lot of 'boilerplate' code. LINK. You might need to install it though. To do so, download the jar file and place it in your STS folder. Then add these 2 lines after -vmargs in your STS.ini file.
-vmargs
. . . .
-javaagent:lombok.jar
-Xbootclasspath/a:lombok.jar