Configuring SocketImplFactory for HttpURLConnection

SocketMain.java

import java.io.IOException;
import java.lang.reflect.Constructor;
import java.net.HttpURLConnection;
import java.net.NetworkInterface;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.SocketImpl;
import java.net.SocketImplFactory;
import java.net.URL;
import java.net.URLConnection;

/**
 * @author <a href="http://shams.web.rice.edu/">Shams Imam</a> (shams@rice.edu)
 */

public class SocketMain {
    public static void main(String[] args) throws IOException {

        Socket.setSocketImplFactory(new SocketImplFactory() {
            @Override
            public SocketImpl createSocketImpl() {
                try {
                    System.out.println("SocketMain.createSocketImpl: retrieving SocketImpl constructor");
                    Constructor socketImplCons = Class.forName("java.net.SocksSocketImpl").getDeclaredConstructor();
                    socketImplCons.setAccessible(true);
                    System.out.println("SocketMain.createSocketImpl: creating SocketImpl instance");
                    SocketImpl si = (SocketImpl) socketImplCons.newInstance();

                    System.out.println("SocketMain.createSocketImpl: retrieving Socket constructor");
                    Constructor socketCons = Class.forName("java.net.Socket").getDeclaredConstructor(SocketImpl.class);
                    socketCons.setAccessible(true);
                    System.out.println("SocketMain.createSocketImpl: creating Socket instance");
                    Socket socket = (Socket) socketCons.newInstance(si);

                    System.out.println("SocketMain.createSocketImpl: configured keep alive on Socket");
                    socket.setKeepAlive(true);

                    return si;
                } catch (Exception ex) {
                    throw new IllegalStateException("Unable to create socket", ex);
                }
            }
        });

        System.out.println("SocketMain.main: Creating connection");
        URL url = new URL("http://www.google.com");
        System.out.println("SocketMain.main: Opening URL connection");
        URLConnection urlConnection = url.openConnection();
        HttpURLConnection httpUrlConnection = (HttpURLConnection) urlConnection;
        System.out.println("SocketMain.main: Awaiting response code");
        final int responseCode = httpUrlConnection.getResponseCode();
        System.out.println("SocketMain.main: Response code = " + responseCode);
    }
}

stdout

SocketMain.main: Creating connection
SocketMain.main: Opening URL connection
SocketMain.main: Awaiting response code
SocketMain.createSocketImpl: retrieving SocketImpl constructor
SocketMain.createSocketImpl: creating SocketImpl instance
SocketMain.createSocketImpl: retrieving Socket constructor
SocketMain.createSocketImpl: creating Socket instance
SocketMain.createSocketImpl: configured keep alive on Socket
SocketMain.main: Response code = 200