Every wonder where the how the Product names get determined? Its somewhat simple, every product name is named for desert using letters of the alphabet starting with 1.5 being cupcake. In build numbers its the first letter.
Thus the next android OS major version, probably 5.x, will be some desert name starting with K or just maybe KeyLimePie. Android OS 6.0 will have a name starting with L, or just for example it might be Licorice.
What happens when they run out of letters? There is a key phrase in the OHA bylines in that the Android OS mobile platform is the FIRST product of the OHA and not the last.