Java's Project Loom & Co - the end for reactive programming?

More often than not, modern and powerful software will at some point have to deal with processing a large amount of events and data. 100 incoming requests per minute can suddenly turn into thousands or more per minute. Appropriately sized hardware can deal with heavy load, if it is available. Well written software intelligently utilizes the available resources, such as memory, network, threads, etc.

The JVM left a lot to be desired here. Especially when it came to managing a limited number of threads. They were an expensive commodity and concurrency is always difficult to implement. Reactive frameworks such as WebFlux, RxJava or Kotlin’s coroutines closed this gap. However, these frameworks are cumbersome. They take some time to really master.

But Project Loom, introduced with Java 21, offers virtual threads as a native Java feature to solve this problem.

I will show how the new Java features compare to established reactive ways. Do they mean the end for reactive programming?