[lmilcin]

If that was "the" problem, why would past versions of IDEA be fast?

Java and JVM are very fast. I know, because I used to do cutting edge algorithmic trading in C with premise that Java is slow and then I was asked to rewrite it to Java with the result being only about 10-30% slower. In this case we are talking receiving messages from network, performing complex processing and sending responses (on another connection) within 5-10 microseconds.

And that was a decade ago, my understanding Java only got better in the meantime, but I am working on more mundane backend/reactive systems and don't require really low latency.

[darksaints]

I never once said Java was slow. I was saying that JIT compiling is a bad fit for an IDE. The workloads present in an IDE cause lots of problems for JIT compilers. And those problems actually can be exacerbated by an evolving code base with lots of new features.

[lmilcin]

> The workloads present in an IDE cause lots of problems for JIT compilers

This would suggest the JIT is a problem. But that is not true, the "workload problem" really means "bloat".

Any software is written for the machine it runs on and Java programs are written for JVM. No machine is perfect and writing performant software requires that you understand peculiarities of the architecture you are working on. If you ignore it it is not the problem of the platform, the problem is you.

Now, the trouble with Java software is what I call "OOP bloat", which is basically overloading the runtime with overheads of abstractions.

What is acceptable level of overhead will depend on how much you value your time vs performance of application so it is not categorically declare it is bad. That assuming the overhead is accomplishing something else (like making the code simpler, easier to develop/maintain).

[darksaints]

Yes, the JIT is the problem. And no, this has absolutely nothing to do with OOP or bloated abstractions. Java is a great language, and the Jetbrains IDEs are written extremely well and have very high coding standards. It is all about the JIT. JITs do really well for code with lots of hot loops and few branches, because inlining and loop optimizations are the classic case for needing execution profiles. But IDEs are the opposite of that...there are branches everywhere, and very few hot loops. JITs are the worst possible compilation model for this type of code, because it is constantly going to be optimizing, deoptimizing, and reoptimizing code. The JIT is just constant overhead for something that should just be profiled and compiled one time.