[FIXED] How to check if internet connection is present in Java?

Issue

How do you check if you can connect to the internet via java? One way would be:

final URL url = new URL("http://www.google.com");
final URLConnection conn = url.openConnection();
... if we got here, we should have net ...

But is there something more appropriate to perform that task, especially if you need to do consecutive checks very often and a loss of internet connection is highly probable?

Solution

You should connect to the place that your actual application needs. Otherwise you're testing whether you have a connection to somewhere irrelevant (Google in this case).

In particular, if you're trying to talk to a web service, and if you're in control of the web service, it would be a good idea to have some sort of cheap "get the status" web method. That way you have a much better idea of whether your "real" call is likely to work.

In other cases, just opening a connection to a port that should be open may be enough - or sending a ping. InetAddress.isReachable may well be an appropriate API for your needs here.

Answered By - Jon Skeet

Answer Checked By - Robin (PHPFixing Admin)