hattery VS reactor-core

While I think there's a lot to love about Java, I think the standard library itself is not an especially great role model. Most of it was written a long time ago and has a fairly antiquated style - lots of mutable state, nullability, and checked exceptions. Not that the library isn't an incredible asset - it's luxuriously rich compared to working in Node.js - but if it were written from scratch today, I suspect it would look fairly different. Eg, the collection classes would use Optional and have separate read/write interfaces.

For an example of "modern Java" I would point at something like this (which I wrote, sorry about the hubris):

https://github.com/stickfigure/hattery

I have been thinking of writing up a series of articles on this. Without going into too much detail:

* IDEA

* Deploy on Google App Engine, Digital Ocean App Platform, Heroku, Elastic Beanstalk, etc - get out of the ops business entirely.

* Guice as the backbone, no Spring/Boot. I wrote a tiny dropwiard-like "framework" to make this easier: https://github.com/gwizard/gwizard but there's a laughable amount of code here, you could build it all from scratch with minimal effort. This is about as lightweight as "frameworks" get because Guice does the heavy lifting.

* JAX-RS (Resteasy) for the web API. IMO this is the best part of Java web development. HTTP endpoints are simple synchronous Java methods (with a few annotations) and you can test them like simple Java methods.

* Lombok. Use @Value heavily. Cuts most of the boilerplate out of Java.

* Junit5 + AssertJ. (Or Google Truth, which is almost identical to AssertJ).

* Use functional patterns. Try to make all variables and fields final. Use collections streams heavily. Consider vavr.io (I'll admit I haven't it in anger yet, but I would in a new codebase).

* StreamEx. Adds a ton of useful stream behavior; I don't even use basic streams anymore.

* Guava. There's just a lot of useful stuff here.

* For the database, it really depends on what you're building. Most generic business apps, postgres/hibernate/guice-persist/flyway. Yeah, folks complain about hibernate a lot but it's a decent way to map to objects. Use SQL/native queries, don't bother with JPQL, criteria queries, etc.

* Hattery for making http requests (https://github.com/stickfigure/hattery). This is another one of mine. I make zillions of http requests, functional/immutable ergonomics really matter to me.

* Github actions for CI.

* Maven for the build. Yes, it's terrible, except for every other build system is worse. Gradle seems like it should be better but isn't. I'd really love some innovation here. Sigh.

I can't stand most http libraries (full of mutable state!) and I spend a lot of time making http calls. So I built a functional/immutable http request library which has been dramatically improving my personal quality of life for about 7 years now. No idea if anyone else uses it, but it doesn't really matter.

Java version: https://github.com/stickfigure/hattery

Typescript version: https://github.com/stickfigure/hatteryjs

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.