Thorntail, previously called WildFly Swarm, is an open source implementation of MicroProfile specifications. It's built on top of mature technologies, and it leverages existing expertise that has been derived from Jakarta EE specifications, patterns, and implementations.
The Thorntail project was born with WildFly/Jakarta EE, but it focuses on modern cloud applications, following the path made by MicroProfile.io (in certain ways). It initially implemented version 1.3 of MicroProfile. You can find its specifications at https://github.com/eclipse/microprofile-bom/releases/download/1.3/microprofile-spec-1.3.pdf.
At the time of writing, Thorntail is in version 2.0.0, and it includes all of the features implemented in WildFly Swarm 2018.5.0.
You can consider Thorntail as a combination of all the benefits of the mature Java EE/Jakarta EE specifications and the flexibility...