There's a lot of complaints about Java being verbose and bad, does Kotlin fix these issues? Does it make it fun again? I personally used to dislike programming until I started using Python at work, and I fell in love again. Syntax, libraries and API design can definitely have a huge impact on how you enjoy what you do.
As for your comment about Activity/Fragments, they've had a few I/O talks going over their thoughts:
I would argue Kotlin is a lot more fun than Java. As for the Fragment lifecycle, it still sucks, but no one forces you to use it. Lots of apps never even use one fragment. Google simply made fragments hoping everyone would make their UIs into reusable components which work better on tablets.
The problem is the benefit you note requires a lot of extra effort and at least one additional layer of abstraction that more than doubles the boilerplate/cruft required to maintain proper UI flow through an application.
Their "solution" is more of a problem than the problem it was meant to solve.
I don't think Java 8 is that bad, it's just mediocre. It's fast and has a good ecosystem.
Yeah, Python is fun, it seems effortless to do stuff there compared to Java. For example, "a = [1]" vs "List<Integer> a = new ArrayList<>(); a.add(1)" - and then you have to compile and run, no REPL to try it out.
Recently I've been using Julia, it's maybe the most fun I had with a language. Some things are much easier to do than in Python - and it's 1 to 2 orders of magnitude faster.
Since you mentioned Julia - are you using it for math or math-related programming, or doing something else? It looks interesting to me, but I'm a web dev (Python on the backend) and don't have much use for most of the math stuff, so I don't know if it's suitable.
As for your comment about Activity/Fragments, they've had a few I/O talks going over their thoughts:
https://www.youtube.com/watch?v=k3IT-IJ0J98
https://www.youtube.com/watch?v=FrteWKKVyzI