Optimising for Concurrency: Comparing the BEAM and JVM virtual machines
the author leaves out Kotlin which adds support for coroutines on the language level and still compiles to java bytecode. These are not classic continuations because they cannot be cancelled, but they&#x27;re still very useful and true fibers.<p>There&#x27;s also the Quasar library that adds fiber support to existing Java projects, but its mostly unmaintained since the maintainers were pulled in to work on Project Loom.<p>Then there&#x27;s Project Loom, an active branch of of OpenJDK with language support for continuations and a fiber threading model. The prototype is done and they&#x27;re in the optimization phase. I expect fibers to land in the Java spec somewhere around JDK 17.<p>I figure its fair to mention these as the authors criticisms are somewhat valid but will not be for very long (few years max?)<p>In summary:
Java will have true fiber support &quot;soon&quot;. This will invalidate the arguments for Erlang concurrency model. They are already outdated if you are okay using mixed java&#x2F;kotlin coroutines or Quasar library<p>The newer Java GC&#x27;s Shenandoah and ZGC address authors criticisms of pause times. They already exist, are free, and are in stable releases. Dare I say they are almost certainly better than Erlang&#x27;s GC. They are truly state of the art, arguably far superior to the GC&#x27;s used in Go, .NET, etc. Pause times are ~10 milliseconds at 99.5%ile latency for multi terabyte heaps, with average pause times well below 1 millisecond. No other GC&#x27;ed language comes close to my knowledge. His points 1 and 2 no longer exist with these collectors. You don&#x27;t need 2X memory for the copy phase and the collectors quickly return unused memory to the OS. This has been the case for several years.<p>Hot code reloading. JVM supports this extensively and its used all the time. Look into ByteBuddy, CGLIB, ASM, Spring AOP if you want to know more. Java also supports code generation at build time using Annotation Processors. This is also extensively used&#x2F;abused to get rid of language cruft