[jeffbee]

I don't know if the stuff about the JVM is even true. I grant that Redpanda is written in C++, but it isn't clear that its performance advantages over Kafka are due to that rather than to the fact that Kafka was implemented in a performance-oblivious way by people who did not know anything about software efficiency. This doesn't reflect on the JVM. You can write a high performing system in Java and the modern JDK is a state-of-the-art toolchain that provides features that many C++ projects struggle with.

[whizzter]

The by far biggest issue for Java is that they still haven't gotten their act together on value-types (project Valhalla), going back in time, the one thing someone should have told the designers was to not to release the erasing generics in Java 1.5 and go for something like C# did with value type structs.

Not really for "purity" issues, but rather due to the fact that memory speeds and main memory latency patterns that started to emerge as problems in the early 00s only got worse over time and having the erasing generics kind of cemented the memory access patterns.

The Java teams has done some truly amazing things in terms of GC research, but much of it is needed simply because the Java and JVM memory model (while "simple") is very allocation-heavy compared to C# that went for value types very early.

Take a peek at the QuestDB source code(Java) for heavy data-manipulation tasks, it's not really written in an idiomatic Java style to avoid GC costs (strongly reminicent of the way some people coded for JavaME back in the early 00s), a C# port would not be entirely idiomatic either but far more so than the existing code.

[ngrilly]

Full agree. Value types are underrated. That's one of the best things about C# and Go. They are increasing performance (with contiguous memory) and reducing GC pressure. I also believe that dynamically typed languages like Python would gain a lot by introducing a form of value types/unboxed values. For example, Cinder, Meta's internal version of CPython, supports what they call "static classes": https://github.com/facebookincubator/cinder?tab=readme-ov-fi....