I know that lots of people have built careers on the JVM and defend it vigorously. Whenever I make a comment that is negative on the JVM, I always get downvoted without fail on HN. I used to be one of these people, after all, so I can relate.
If I truly cared about performance these days, I’d use C++ or Rust. Otherwise, I’d use a language like golang with reasonable default GC behavior and allocation patterns - where I know the daemon I write won’t use more than 100-200Mb, and probably even less, and will typically have sub-ms pauses. I think even most scripting languages, like Ruby/Python, have reasonable memory usage and GC patterns for web development, but I’m not as familiar with them.
I probably care more about energy consumption these days though. And again, the JVM is the worst offender. The average developer building a Java web app will create something which consumes gigabytes of memory usually. These apps tend to spend the majority of their CPU time allocating and GCing memory. I can only guess how much server time has been consumed to satiate the memory hungry needs of the JVM.
No. If you use the JVM you might well care about performance. If you care about performance, you should consider the JVM.
> I spent years as a performance engineer on HFT trading systems tuning JVMs.
The JVM is not designed to give you 100% performance (of the ideal offered by the hardware). It's designed to give you the easiest means of achieving ~95%, provided you're OK with some nondeterminism.
> I’d use a language like golang with reasonable default GC behavior and allocation patterns - where I know the daemon I write won’t use more than 100-200Mb, and probably even less, and will typically have sub-ms pauses.
You'd be wrong, because JDK 14 will most likely give you substantially better performance than Go out of the box; JDK 15 and 16 even more so.
BTW, the footprint and performance profile of JDK 14 is worlds apart from JDK 8. The JVM has been undergoing some very big changes in the last couple of years.
> And again, the JVM is the worst offender
Nope. https://greenlab.di.uminho.pt/wp-content/uploads/2017/09/pap...
Granted the parent was anecdotal with their own experiences too, you could at least address the points. E.g. to the point of achieving 100-200Mb daemons, you might reference what RAM footprint you typically expect/experience from a similar program running in JDK 14-16. Rather than just:
> You'd be wrong, because JDK 14 will most likely give you substantially better performance than Go
What helps .NET is the design since the early days to support value types and the introduction of Midori learnings into C# 7 and later for low level programming.
Probably the best thing about the JVM that, AFAIK, no other platform does is it gives you an option for which GC you use. Not only is that an option, but you are spoiled with options. ZGC, G1GC, Shenandoah, The parallel collector, the serial collector. Pick the right one for the job!
But beyond that, they are infinitely tuneable (Not that you should usually). Again, not something that almost any other platform offers.
