[jayd16]

I think certain paradigms were completely shifted compared to the PC space.

  -Revamped permissions
  -App packaging/name spacing/consistent installation
  -IPC was redesigned as asynchronous Intent blobs on Android
  -Urls becoming first class citizens at the OS level
  -More consistent background app apis (and eventually better ways to track them)

I could come up with more but I think there's actually a very big difference. But yes, its all built on top of older Java and obj-c libs.