That window seat is WONDERFUL!
I do kinda have a thought re: getting him to respond better to others -- may not help at all, but just throwing it out there in case it may help or give food for thought or whatever -- whoever in the video kept reaching for him was really not respecting his cues to back off - just kept reaching and reaching and reaching and reaching and reaching.
Java was just doing air jabs, then had to escalate to skin contact because he wasn't being "listened to" in that moment. (Unless that's a game you guys like to play -- like keep away or something, and you're all just playing, but I didn't get that sense.)
That's not to say at all that you're not the most amazing parront and family in the world to Java! But just in that moment, in that video, to me for a parrot (because they are just so, so sensitive, and the difference in pretty much anything between wonderful and terrible is barely detectable to us clumsy humans -- be it touch, or where to sit, or what to eat, etc. - they are just so, so discerning and make such fine discriminations) - he was really being pushed to and not "listened" to, so to speak.
Is it possible that others who go to interact with Java don't read his body language nearly as well as you do, and that may be some small part of why he won't take food or drink from them, or have any positive interactions with them, etc? Maybe they need really detailed guidance from you in how to interact with him in a way that makes him feel like he is being listened to and not pushed to, say, accept petting he doesn't want, etc.?
I don't think there's anybody in the world who could or would do more for Java than you! But he's got to expand his circle of friends! It's only healthy for you both -- you may well have to go away for a day or something, like you said.