jFonia is a framework/API for music, focusing on symbolical (discrete) data such as notes, clefs, measures etc.
It is a low level framework, aiming to facilitate the development of high level music software, such as score players, viewers, editors, analysis and composition tools etc.
The Freesound Project is a collaborative database of Creative Commons licensed sounds. Freesound focusses only on sound, not songs. This is what sets freesound apart from other splendid libraries like ccMixter. New to this site? Read the What is Freesound page to learn more!