Are there still any reasons why one should choose Java instead of .Net for new developments?
Maven, love it or hate it, can do a staggering number of things, some of them very useful.
JAX-RS servers and clients are more robust IME on Java. (Just try to find a capable path+querystring builder for .NET.)
JDBC is still the gold standard for database connectivity.
I still have a repository where Surefire (hah) refuses to run any tests. Impossible to debug. No, that pile won't be missed.
For ASP.NET controllers, I'd use attribute routing's URL generation: https://docs.microsoft.com/en-us/aspnet/core/mvc/controllers...
If you want a separate library for use outside of ASP.NET, and you want something more sophisticated than UriBuilder, there are several out there. I've used Superscribe in the past, but I just looked around and Flurl looks pretty neat: http://tmenier.github.io/Flurl/
Haven't yet found the .NET equivalent to allow webtarget.path("foo").path("bar").query("hello", "yes") without making the user try to remember which URI query-part-escaping static method is appropriate.
Now that said, Flurl looks to have this pretty well covered, neat library!
The funny thing about that statement is that it's both true and insanely sad. JDBC is downright terrible but having a standard DB access layer has contributed a lot to Java's rise over the years.
I personally acknowledge that C# is a nicer language, but on Macs and Linux machines I have not had a great experience using it so far. I think if you try it today, you're basically an early adopter. If you're going to be an early adopter, the barn doors are wide open and I'm going to make serious consideration of Python, Haskell or Go.
Probably because Java runs without problems on (Windows) and (IX platforms without major problems).
FTFY ;-)