On the JVM, threads are the de-facto, fundamental instrument of concurrency. Multiple threads live in the same JVM; they share the heap space and compete for resources.
JVM threads are the operating system threads. Java wraps an underlying OS thread as an instance of the
java.lang.Thread class and builds up an API around it to work with threads. A thread on the JVM has a number of states:
Terminated. A thread is instantiated by overriding the
run() method of the
Thread class or by passing an instance of the
java.lang.Runnable interface to the constructor of the
Thread class. Invoking the
start() method of a
Thread instance starts its execution ...