BlockHound VS reactor-core

There is a great tool called Blockhound we can use to detect if/when we have a blocking call in our application. This way, we can ensure that we don't break the non-blocking nature of our application by mistake while developing new features. Setting it up is fairly straightforward.

There's even a test library to detect them: https://github.com/reactor/BlockHound

One of the talks in my current portfolio is Migrating from Imperative to Reactive. The talk is based on a demo migrating from Spring WebMVC to Spring WebFlux in a step-by-step approach. One of the steps involves installing BlockHound: it allows to check whether a blocking call occurs in a thread it shouldn't happen and throws an exception at runtime when it happens.

The first step is to make the application compatible with GraalVM. We need to remove Blockhound from the code. Blockhound allows verifying that no blocking code runs in unwanted places. It's a Java agent that requires a JDK, not a JRE. It's great for a demo, but it has nothing to do with a production application.

I was exploring reactive streams with project reactor and I encountered a use case where I needed to skip to the next event if an error occurred during the processing of the current event (e.g. deserialization issue).

Kotlin also has a construct for asynchronous collections/streams. Kotlin's version of AsyncSequence is called a Flow. Just as Swift's AsyncSequence builds upon prior experience with RxSwift and Combine, Kotlin's Flow APIs build upon earlier stream/collection APIs in the JVM ecosystem: Java's RxJava, Java8 Streams, Project Reactor, and Scala's Akka.

Java's projectreactor.io ? It is widely used in Java world, see Spring WebFlux.

I guess more a closer comparison would be with the Project Reactor https://projectreactor.io/ which is also a low level framework for data processing.

Spring Framework is one of the most popular choices for web applications. It comes with a great ecosystem, tooling, and support. Spring applications are mainly written in Java. While they can serve quite well in many different domains and use cases, they may not be a good fit for modern-day applications which require low-latency and high-throughput. This is where the reactive programming paradigm could help because the paradigm is designed to address these issues by its non-blocking nature. Spring already supports reactive programming via Project Reactor.

The reactive streams API provides the specification for non-blocking async streams processing with back pressure mechanism, and Project Reactor is an implementation written in java.

https://projectreactor.io/ https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html https://rxjs.dev/ https://developer.android.com/kotlin/coroutines https://developer.apple.com/documentation/combine

With respect to Loom, it could be much easier for synchronous and reactive code to interoperate using schedulers that take advantage of Loom. The impact of Loom on Project Reactor was discussed in #3084, you might find it interesting.