BITPlan's RESTFUL software is mostly based on Java and the Jersey framework. see e.g. https://stackoverflow.com/questions/tagged/jersey
As of 2017 we use maven as a build system and Eclipse as the IDE. For the front end we use plain HTML, Bootstrap and JQuery.
To ease the separation of presentation and logic we use the Rythm template engine. As a base framework we have created the SimpleREST project, which is published on github. The corresponding API interface definitions have been separately published at SimpleREST-API If you are looking at this article from our Wiki frontend then the framework has been part of the process to render this page.