ObjectDAO

object DAO will save your object as .json file make instance:

ObjectDAO o = new ObjectDAO(this, GRepo.Mode.LOCAL);

Modes :LOCAL,EXTERNAL,CACHE
local: app privete storage (user and other apps can not access)
external: root of public storage (user and other apps can access)
cache: files in this mode will be removed by cleaner apps
save:

o.Save("user",yourObject);

load:

o.Load("user",User.class);