Sandbox / Access the memory

???1 - What it is and which the concept of “Sandbox” in the J2ME?
???2 - We know that in the CLDC no Midlet obtains to have access the memory of other applicatory ones of the cellular one as Calendar and Contacts, for example, nor of other Midlets that are not of the same “suite”. This also happens in the CDC? How it is the security in the CDC?