test/jdk/java/net/URLConnection/UNCTest.java

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/**
 * @test
 * @bug 4401485
 * @requires (os.family == "windows")
 * @modules java.base/sun.net.www.protocol.file
 * @library /test/lib
 * @summary  Check that URL.openConnection() doesn't open connection to UNC
 */

import jtreg.SkippedException;
import sun.net.www.protocol.file.FileURLConnection;

import java.io.File;
import java.net.InetAddress;
import java.net.URI;
import java.net.URL;
import java.net.URLConnection;

public class UNCTest {
    public static void main(String[] args) throws Exception {
        // Get the "computer name" for this host
        String hostName = InetAddress.getLocalHost().getHostName();

        // UNC path which always exists with Administrative Shares enabled
        String path = "\\\\" + hostName + "\\C$\\Windows";

        // Skip test if Administrative Shares is disabled
        if (! new File(path).exists()) {
            throw new SkippedException("Administrative Shares not enabled");
        }

        // File URL for the UNC path
        URL url = new URI("file://" + hostName + "/C$/Windows").toURL();

        // Should open a FileURLConnection for the UNC path
        URLConnection conn = url.openConnection();

        // Sanity check that the connection is a FileURLConnection
        if (! (conn instanceof FileURLConnection)) {
            throw new Exception("Expected FileURLConnection, instead got "
                    + conn.getClass().getName());
        }

        // Verify that the connection is not in an already connected state
        conn.setRequestProperty( "User-Agent", "Java" );
    }
}