Quite a few of the top HFT firms use Java, almost exclusively.<p>The trick is to segment your critical path code (whatever is executing the actual trades and is highly susceptible to delays) from any business logic. Then you can focus on making critical path components fast - disable GC completely, keep object allocations way down, audit every line of code, etc. With such a setup you can even do better than typical C++ because you avoid virtually all object allocation&#x2F;deallocation costs that C++ has. Java object allocation is dirt cheap, it just hurts when you GC, which you can basically avoid or schedule for out of hours. If you want better I would not bother with C++ at all personally, but use C &#x2F; assembly or even look at FPGA type setups.