Java threading 
Threads are the basic unit of concurrency in Java. Threads provide the advantage of reducing program execution time by allowing your program to either execute multiple tasks in parallel or execute on one portion of the job while another waits for something to happen (typically input/output (I/O)).
HFT architecture heavily uses threads to increase the throughput, as we mentioned in Chapter 7, HFT Optimization – Logging, Performance, and Networking. Multiple threads are created to do tasks in parallel. Adding threads to a program that is completely CPU bound can only slow it down. Adding threads may assist if it's totally or partially I/O bound, but there's a trade-off to consider between the overhead of adding threads and the increased work that will be done. We know that the underlying hardware (CPU and memory resource) will limit this throughput. If we increase the number of threads beyond a certain limit (such as the number of cores or the number...
