Difference between MMM and LLL (Stand alone value) in SimpleDateFormat object

I am trying to find out what the difference between three Ls (LLL) and three Ms (MMM) in the declaration of a SimpleDateFormat object ( i.e. new SimpleDateFormat("MMM/LLL dd, yyyy") ). I have searched the web and the documentation, but the only thing I could find is that the one is used for stand-alone cases and the other for context-sensitive ones. Can anyone help me on what's the difference between those formats? Thanks!