"What is Python? Python is an interpreted, interactive, object-oriented programming language.
It incorporates modules, exceptions, dynamic typing, very high level dynamic data types, and classes.
Python combines remarkable power with very clear syntax. It has interfaces to many system calls and libraries,
as well as to various window systems, and is extensible in C or C++.
It is also usable as an extension language for applications that need a programmable interface.
Finally, Python is portable: it runs on many brands of UNIX, on the Mac, and on PCs under MS-DOS, Windows, Windows NT, and OS/2." (Python FAQ)
"What is JPython? JPython is a new implementation of the Python programming language which is designed to run on the Java Platform.
It consists of a compiler to compile Python source code down to Java bytecodes which can run directly on a JVM,
a set of support libraries which are used by the compiled Java bytecodes,
and extra support to make it trivial to use Java packages from within JPython." (JPython FAQ)