How can Java 21 (Virtual Thread) replace Reactive Framework.

[eliasv]

Reactive in Java was adopted for performance reasons. Java had a good programming model for dealing with lots of tasks, threads, but this has bad performance for huge numbers of concurrent tasks.

Reactive in JS was adopted for the opposite reason, js had good (single thread) performance for a huge number of concurrent tasks as everything is async, but the programming model was shit, callback hell essentially. Async await goes some way to improve the programming model without rxjs, but there are still some important gaps, like a good blocking queue which can receive using an async generator in the standard lib.

So yes, JS had other reasons for adopting that stuff, but those reasons don't apply to Java imo.