The terms do have diffent meanings, though they refer to similar contexts.
Portability, or code portability, I understand to refer to the ability to take code that runs on one platform, and port it to (i.e. make it run on) another platform.
Java claims a high-degree of portability, and rightfully so, in my opion, since, to a large extent, a J2SE 1.4 app that runs on Windows will run the same on Linux and Mac OS X. In this sense, Java claims such a high-degree of portability that it is often referred to as being platform independent.
Are these conepts clear?