programming using networkmanager

["Syed Md. Ashraful Karim" <ashraful ansur no>]

Hi
I want to write an application to detect any changes in the network
interface (up and down) and the system will some task depending on that.
Then I need the active up interfaces too. 
Can anybody help me giving any reference how I can I handle such up/down
of interfaces event from NetworkManager. The code can be written in Java
or C/C++.
thanks in advance.

/ashraf