There are some libraries to implement WebSocket usage in an unobtrusive fashion. Apparently, there are many libraries out, but what I really looking is a modern and small library which I can use on Android or Java in generall to implement my WebSocket usage from the client side.
So far I have found:
I am missing a bit the differences of the differnet libraries. JAX-RS 2.0 for instance seems to be a great foundation for a lot of implementations, but I also went with Square's Retrofit for my RESTful Client because it was just leaner and easy to integrate.
nv-websocket-client-1.3.jar
(released on 2015-05-06) is 62,854 bytes and it does not require any external dependencies. See "WebSocket client library (Java SE 1.5+, Android)" for details. – Takahiko Kawasaki