This week's giveaway is in the Cloud/Virtualization forum. We're giving away four copies of Secure Financial Transactions with Ansible, Terraform, and OpenSCAP and have Lucian Maly on-line! See this thread for details.
You could try a ping of sorts (using InetAddress.isReachable) to a server on the Internet, but that will also fail if the remote host is down.
As for the notification Windows provides, that may be available but through JNI only, or it may not be available at all. You can also check out java.net.NetworkInterface but I'm not sure it can help you out with this.