To quote from: http://unity3d.com/support/documentation/Manual/Plugins.html
"To do that first locate the classes.jar shipped with Unity Android. It is found under the installation folder (usually C:Program FilesUnityEditorData (on Windows) or /Applications/Unity (on Mac)) in a folder called PlaybackEngines/AndroidPlayer/bin. Then add that classes.jar file to the classpath used to compile the new activity. "
But, there isn't such a directory on Mac - at least, I can't find that in Applications/Unity ... does anyone know wherewhere to find classes.jar?
asked Nov 04 '11 at 07:26 AM
Right-click on your 'Unity.app' in the applications window, and select 'Show Package Contents'. This will expand the .app out into a small filesystem, in which you can find the files you are looking for.
This happens because applications on MacOS are evaluated by Finder as executables, but are actually folders which get special treatment- the actual executable is buried deep within the package (usually at Contents/MacOS/something). This allows a program to have all its required resources neatly packaged inside itself, without needing to do something convoluted like uncompressing a tarball of some kind at runtime.
answered Nov 15 '11 at 07:13 AM