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I can only answer a part of the question i.e what is a 'sandbox':
It is a protected and limited environment where applications (like Java programs downloaded from the Internet) are allowed to "play" without risking damage to the rest of the system. The R&D department at many software and computer companies is sometimes referred to as a 'sand box'.
(From Wikipedia encyclopedia): In computer software, sandbox is an informal name given to the limited execution environment in which untrusted programs are run. The boundaries of this notional box limit the scope of a malicious program to cause damage to the computer system as a whole.
Similarly, in software development the term is used to refer to a test system which replicates (often in reduced size or capacity) the actual computing environment for which software is being developed. The presence of such a safe, controlled environment allows developers to try experimental code without fear of damaging a mission-critical system.
Hope this helps.