I believe I misread your first sentence, I thought you said every prop shop IS using Java. I have seen this specific claim so many times that I must have filled

I believe I misread your first sentence, I thought you said every prop shop IS using Java. I have seen this specific claim so many times that I must have filled in the word. The reason not to use java for low latency latency is that good low latency Java is pretty much only Java in a syntactic and to some degree object sense. Avoiding allocation permeates everything, and is just not worthy the battle. You basically try to write C++ in Java, except without the language features of C++ to help with memory management and layout, and wit the added burden of having to worry about pools and primitive boxing and the runtime at every corner. You would also be surprised though at how little hardware has replaced C++ on Linux with good user space networking. Not that many trades are pure latency arb, so getting that last microsecond or two just isn’t worth the effort. It’s much more common to see hardware in fixed-function locations than it is to see hardware running the meat of a strategy.