How to track changes in whole file system?

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C#

Java

Hello,
I want to keep track of all the changes made in file system through my application.
Changes means currently which files are open,modified etc.
Means after occurring event for opening,creating,modifying and deleting the file, my software will get the notification with file name and its action performed on it.
For this i don't know which classes , API's are useful in java/C#.
If anybody have any idea then please help me.

Thanks
Ramkrishna