Most frameworks for java help simplify programming. These are called "API's" (Application programming interface). To integrate one into your project, you must download the framework, then include its source with your source, and call its methods.
Also lets say a came across a java framework of some sort, is it possible for me just to download it and somehow configure netbeans to understand that framework as well as the original so now all of a sudden my code can import more classes and do more stuff or have i got this completely wrong? or is that plug-ins?