Java gives you a flexible object oriented language and an incredible set of libraries. It's got an archiver for artifact and dependency management. It now has lambdas and has FRP style stream programming. I'd say it's kept up pretty well with modern fashion, while it's been doing other things far longer than newer, more popular languages. Take Swift, now my daily driver (which I love so much compared to ObjC, which I moved to after Java)... an example of something Java had way before Swift is "Protocol Oriented Programming". Also, Swing's GridBagLayout predates iOS' AutoLayout and CSS (edit: don't know where I was going with CSS haha...). Everything old is new again, and I'm sure Java reinvented a few wheels of it's own.

Also keep in mind that React is a library, not a language. If you want to compare things, compare Javascript to Java, or the Java stdlibs to React. Maybe that's what you meant when you said Java.

IMO, Java and its libraries are nicer to work with solely due to its static nature and OO design. It is worlds apart from a scripting language when you need to refactor, or even just understand, legacy code. And if you can't even run tests on that legacy code anymore, like a React project over a year or two old?

What are the better patterns and productivity boosts you get from React vs. a Java ecosystem?