What the author is describing is not a “low latency system” with regards to finance. That term is used to describe a system that will successfully make a trade

What the author is describing is not a “low latency system” with regards to finance. That term is used to describe a system that will successfully make a trade that is regarded as a good trade at the time of a signal. For example, if an order comes in to sell XYZ, and Optiver/Citadel/Virtu all want to buy it, a low latency system is one where you can buy that order at least some of the time. In one sense, the author is right that C++ based systems do not suffice to trade that order, but he is very wrong that Java ones do. His justification that banks use Java is not compelling. Morgan Stanley is the only bank that is remotely competitive technologically. And his justification that dev time is faster on Java is just ridiculous. It’s even faster on Python, but we aren’t talking about dev time. We’re talking about building systems that can reliably execute ingress-egress in less than a microsecond. Even using kernel bypass cards and assembly doesn’t get you there. So, no, Java isn’t a good choice for low latency systems.