Threads are the fundamental model of program execution in a Java program,
and the Java language and its API provide a rich set of features for the creation
and management of threads.
All Java programs comprise at least a single thread
of control—even a simple Java program consisting of only a main() method
runs as a single thread in the JVM.
Java threads are available on any system that
provides a JVM includingWindows, Linux, and Mac OS X. The Java thread API
is available for Android applications as well.