I am developing a Java Desktop Application that access internet. It is a multi-threaded application, each thread do the same work (means each thread is an instance of same Thread class).

Now, as all the threads need internet connection to be active, there should be some mechanism that detects whether an internet connection is active or not.

Q1. How to detect whether the internet connection is active or not?

Q2. Where to implement this internet-status-check-mechanism code? Should I start a separate thread for checking internet status regularly and notifies all the threads when the status changes from one state to another? Or should I let each thread check for the internet-status itself?

Q3. This issue should be a very common issue as every application accessing an internet should deal with this problem. So how other developers usually deal with this problem?

Q4. If you could give me a reference to a good demo application that addresses this issue then it would greatly help me.