Checking file size always [duplicate]

This question already has answers here: Closed 11 years ago.

Possible Duplicate:

Size of folder or file

How to do such a loop that will check the file size, and if it change then output something ? Not only once, but every time to sho开发者_运维技巧w something if the size change

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Java 7 has support for this without polling the file system see here