Question

In Java I’m trying to verify that a URL exists. I do this by creating a URL object, then calling URL.openConnection, then calling URLConnection.connect(), then calling URL.openStream(). None of these throw an exception with this URL: “http://”, which makes no sense.

I need the method to be protocol independent.

Answer 1

Get the response code:

URL url = new URL("http://");
HttpURLConnection   conn = (HttpURLConnection)url.openConnection();
int rc = conn.getResponseCode();
conn.disconnect();

If it doesn’t throw an exception, the URL exists. This one threw

Exception in thread "main" java.lang.RuntimeException: java.lang.IllegalArgumentException: protocol = http host = null

for me.