Connect with iOS and Android clients to SockJS Backend
Maybe it's more than a year since the question was asked. But, because it's getting in the first results when Googling for SockJS+Android. So, I am posting my answer.
From my experience with a recent project I worked on, we were able to use a STOMP client - like the one here- to connect to Spring Websocket backend from native Android app.
And from the browser, you can still use SockJS client to gain across browsers compatibility to websockets with fallback.
A note to mention that when using only STOMP client to connect to native websocket the URL will be something like ws://mydomain/SockJSEndpoint/websocket, and when using SockJS client from the browser the URL will be like http://mydomain/SockJSEndpoint.
Please find below useful references related to your requirement for both iOS and Android