> If a webapp performs similar to this experiment, I could rewrite it in almost any other language and I’d cut the required number of servers in half or more.
Nope. Because you gain in performance where you lose on memory. If you add more RAM, you'd pay for less hardware and consume less energy.
Anyway, if you last experienced Java in version 8, try 14. It's not what you might remember. You'd likely see a 10-40% reduction in cost-per-transaction, plus very low pauses with the new GCs. OpenJDK's VM in 14 is just significantly different from what it was in 8.
no matter how good a gc gets, if it does need to do double the work of another gc it is not a problem of the gc. it is that too much allocation is needed even for simple things. java tried to tune their gc over and over instead of just fixing the problem. allocations.
That's true, and while Valhalla will help close the gap, it is important to understand that Java's goal is not to be the fastest language, but to be the language where it's easiest to get to 95% of full performance potential. I don't think any other language achieves that as well as Java. The question, then is how much you're willing to pay for that extra 5%.
In other words, for every Java program X, there exists a C/C++ program Y that's at least as fast. But is the cost of writing Y worth it given the particular performance benefit? The reason Java is so popular is that the answer is very, very often no. And remember that the lower Java costs are not just in the "coding costs" of writing and maintaining, but also in observability. These days, thanks to the Java Flight Recorder, Java gives you unparalleled insight into what your application is doing for very little overhead.
we are basically struggeling to find people in the java domain, the amount of people with c# knowledge in my area is so much bigger.
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however I'm personally a heavy java user (or scala should I say) unfortunatly the more things I did in c# the more I missed stuff especially in plain java. I thing the oracle takeover of java held the language back a bit for a few years. I mean if I look at the releases, they started to catch up with their new model, etc. which is good.
and I think what java these days are missing is a project like django/ror or aspnet.core which drives the web forward with a fully integrated web framework that does not suck. don't get me wrong spring looks promising, but it tries to fullfil every role by being "flexible" which it probably shouldn't be. enforce something. give us a nice little ORM that is not enterprise, look at linq. and especially don't be so enterprisy.