[Java] New Twitch API - Streams return empty Json when ?user_id is set

Sadly no, but you can still use v5’s endpoints:
PUT https://api.twitch.tv/kraken/channels/<channel ID> to update a channel
GET https://api.twitch.tv/kraken/channels/<channel ID> to get a channel’s current information
(More at https://dev.twitch.tv/docs/v5/reference/channels/)

Helix is missing a lot of stuff, that is the reason v5 still remains functional. If you need to use enpoints not available in Helix, check Kraken.