While working on JDK-8202177 I found that URL.openStream() might be very slow, and looks like it does not necessary depend on the network performance.

I have tested it on macOS using this program:

public final class URLOpenStream {

    public static void main(final String[] args) throws Exception {
        connect("https://bugs.openjdk.java.net");
    }

    private static void connect(final String path) throws IOException {
        URL url = new URL(path);
        for (int i = 0; i < 3; ++i) {
            long start = System.currentTimeMillis();
            InputStream is = url.openStream();
            long end = System.currentTimeMillis();

            System.out.println("connect in " + (end - start) + "ms");
            is.close();
        }
    }
}
===========
Output:
connect in 1216ms
connect in 275ms
connect in 233ms

Sometimes initial time is dropped to a few seconds. And initial submitter reports tens of seconds.