Asynchronous Http and WebSocket Client library for Java
An Asynchronous HTTP Library for Android
A fast async http client based on netty
An asynchronous HTTP client built on top of Java's HttpURLConnection
http-kit is a minimalist, event-driven, high-performance Clojure HTTP server/client library with WebSocket and asynchronous support
The Grizzly Async Http Client (GAHC) library purpose is to allow Java applications to easily execute HTTP requests and asynchronously process the HTTP responses
RESTful Web Services using Apache Shiro 1.2.3, JBoss RestEasy 3 and Google Guice 3 with Asynchronous HTTP Request Processing support.