Hello every body, JDK 1.4 provides non blocking I/O calls in the package java.nio . So, the execution line of a program, won't be paused waiting for a read or a write (since it is done in a separate thread), and consequently the CPU would never be idle !!! In this case, one can think that creating threads (aThread.start() etc...) is useless, since one wants to create threads only to make the CPU always busy. What do you think ?