I can't think of a slower language. Then all your IPC is done through json as if everything was a website hundreds or thousands of miles away instead of something more sensible such as a shared memory.
Won't beat Rust on most benchmarks, of course.
Software engineer time is still often the primary cost metric, but Java didn't ever get actually fast - things like constant pointer chasing and poor cache utilization still hurt it significantly in "regular" code. So, too, does the complete lack of compile time optimizations and limited JIT thoroughness & comprehensiveness.
There's pockets of people doing Java + performance, but they are far & away the exception and they are frustratingly insular about what they do & why they do it. And yeah it tends to often go against every bit of guidance from things like Effective Java & similar.
It still takes many seconds to just start the program
Maybe the JRE is simply a pain to start ?