React for example has a solid mathematical foundation and that's why it provides really good, clean abstractions. Spring is just a bunch of annotations and if you haven't done it for half of your life it really isn't clear why I have to write an empty! class that has 6 annotations on it, just to get the plumbing right for configuration. Smells like what I'm doing there should just be a function instead but maybe that's also partly Java being Java.

Yes it's very mature etc but at the end of the day it's just a collection of stuff that evolved over time. It's a framework written by developers, not mathematicians; a BeanPropertyRowMapper is likely something that happened on accident, react's algebraic effects are not.

Maybe it's not a fair comparison because react is super slim and spring (boot) is huge but when using it you have to work your way through endless baeldung tutorials to figure out which annotations to put onto your methods with no clear design. I also found asp.net easier to work with.

Reason it reminds me of jQuery is because it's everywhere. A coworker of mine just wrote some websocket code that should be really great and reusable but it uses spring annotations extensively so you can never use his code without spring. But it doesn't really matter because if he wants to reuse the code in another java project, spring will likely be there. And that's a level of hodgepodge that jQuery achieved back in the day too.

Guess what I want to say is that not all of web is "badly thought out" like the above poster insinuated.