An asynchronous http client in Java, with a clean, callback-based API, using Netty 4.x
Simple and lightweight HTTP client for Android
Asynchronous Http and WebSocket Client library for Java
Google HTTP Client Library for Java
This is a java based Vault client library for communicating with Vault via HTTP.
Unirest in Java: Simplified, lightweight HTTP client library.
Feign makes writing java http clients easier
An in-app HTTP inspector for Android OkHttp clients
Asynchronous socket, http(s) (client+server) and websocket library for android. Based on nio, not threads.