[worked around] Docker HTTP(S) API no longer available in beta9?

The TCP socket going away was an accidental byproduct of the networking changes, it is still there but you cannot at present reach it. It was not intended to be a permanent feature though, and will probably go away in a few weeks when Windows no longer needs it. We may add an https socket at some point, unconfirmed. I think you are best off using socat or running tools in a container, or using a container to forward the socket to localhost (ie socat in a container with published port) until Java is fixed to be able to understand sockets. There will be the same issue on Windows as new docker uses a named pipe there.