Spark Java HTTP to HTTPS redirector

HttpsRedirector.java

import java.io.Closeable;
import java.net.InetSocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;

public final class HttpsRedirector {
    private final ServerSocketChannel server;
    private final Selector selector;
    private final byte[] redirectResponseHeaders;

    public HttpsRedirector(int http_port, String https_url) throws Exception {
        server = ServerSocketChannel.open();
        server.configureBlocking(false);
        server.bind(new InetSocketAddress(http_port));

        selector = Selector.open();
        server.register(selector, SelectionKey.OP_ACCEPT);

        redirectResponseHeaders = ("HTTP/1.1 301 Moved Permanently\r\nLocation: " + https_url + "\r\n\r\n").getBytes();
    }

    public void start() {
        new Thread(() -> {
            try {
                while (true) {
                    if (selector.select() > 0) {
                        final Set<SelectionKey> keySet = selector.selectedKeys();
                        final Iterator<SelectionKey> iterator = keySet.iterator();
                        while (iterator.hasNext()) {
                            final SelectionKey selectionKey = iterator.next();
                            if (selectionKey.isAcceptable()) {
                                redirectClient();
                                iterator.remove();
                            }
                        }
                    }
                }
            } catch (Exception ignore) {
            } finally {
                closeResource(selector);
                closeResource(server);
            }
        }).start();
    }

    public void stop() {
        closeResource(selector);
        closeResource(server);
    }

    private void closeResource(Closeable c) {
        if (c != null) {
            try {
                c.close();
            } catch (Exception ignore) {
            }
        }
    }

    private void redirectClient() {
        SocketChannel client = null;
        try {
            client = server.accept();
            client.socket().getOutputStream().write(redirectResponseHeaders);
            client.socket().getOutputStream().flush();
        } catch (Exception ignore) {
        } finally {
            closeResource(client);
        }
    }
}

TetstServer.java

public final class TestServer {
    public static void main(String... args) throws Exception {
        port(443);
        secure(".config/keystore.jks", "password123", null, null);
        final HttpsRedirector redirector = new HttpsRedirector(80, "https://localhost/");
        redirector.start();

        get("/", (request, response) -> {
            halt(200, "Hello World");
            return response;
        });
    }
}