HttpCore is a set of low level HTTP transport components that can be used to build custom client and server side HTTP services with a minimal footprint. HttpCore supports two I/O models: blocking I/O model based on the classic Java I/O and non-blocking, event driven I/O model based on Java NIO.
Some examples of HttpCore components in action can be found here
Javadocs
API compatibility reports
HttpCore components strive to conform to the following specifications endorsed by the Internet Engineering Task Force (IETF) and the internet at large: