All modern computer hardware architectures and operating systems are capable and optimized for multi processor system and multi threaded system. Process Vrs Thread: Process is heavy weight where as Thread is light weight. Thread is light weight because process uses it's own address space and thread shares the Process's address space. So Threads are considered to be subset of a process. more over threads consumes less OS resources in terms of physical memory and uses CPU time at most. Junior programmers think concurrency is hard. Experienced programmers think concurrency is easy. Senior programmers think concurrency is hard. _ Java Concurrency Essentials by Martin ...