History of Android:
The history and versions of android are important to know. The operating system version code names of android started from A to J currently, such as Aestro, Blender, Cupcake, Donut, Eclair, Froyo, Gingerbread, Honeycomb, Ice Cream Sandwitch, Jelly Bean, KitKat and Lollipop.
What is API level?
Application Programming Interface(API) Level is an integer value that distinctly identifies the framework API revision offered by a version of the Android platform, such as
|Platform Version||API Level||VERSION_CODE|