Settings settings = Settings.builder().put("cluster.name", "xxx")
                    .put("xpack.security.transport.ssl.enabled", false)
                    .put("xpack.security.user", "xxx:xxx")
                    .put("client.transport.sniff", true).build();
try {
    client = new PreBuiltXPackTransportClient(settings)
            .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("xxx.xxx.xxx.xxx"), 9300))
            .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("xxx.xxx.xxx.xxx"), 9300));
} catch (UnknownHostException e) {
    e.printStackTrace();
}