NanoHTTPD
Tiny, easily embeddable HTTP server in Java
... months. The next release will come soon, and there will not be any more "intended" major changes before the next release. If you want to use the bleeding edge version, you can clone it from Github, or get it from sonatype.org (see "Maven dependencies / Living on the edge" below). Fully functional HTTP(s) server consisting of one (1) Java file, ready to be customized/inherited for your own project. Simple examples on how to customize NanoHTTPD.