Continuing the discussion from Tellstick binding for OpenHab2:
So switching to the Jetty Http Client causes an issue for me. What about OAuth, the library I currently use is connected to the Apache HTTP Client. @Kai do you have any recommended OAuth library ?
Just want to add that Oltu does not work since it is only OAuth2, I need OAuth1.
Sorry to answer slightly late, I didn’t see your ping at the time and just came across it by chance now. 
OAuth client is still an open issue, though, I therefore just created https://github.com/eclipse/smarthome/issues/4551 for further discussion.