private boolean pingServer() throws ProxyCacheException {
        String pingUrl = getPingUrl();
        HttpUrlSource source = new HttpUrlSource(pingUrl);
        try {
            byte[] expectedResponse = PING_RESPONSE.getBytes();
            source.open(0);
            byte[] response = new byte[expectedResponse.length];
            source.read(response);
            boolean pingOk = Arrays.equals(expectedResponse, response);
            Logger.info("Ping response: `" + new String(response) + "`, pinged? " + pingOk);
            return pingOk;
        } catch (ProxyCacheException e) {
            Logger.error("Error reading ping response");
            return false;
        } finally {
            source.close();
        }
    }
Pings {@link HttpProxyCacheServer} to make sure it works.
VideoCache/src/main/java/com/yc/videocache/Pinger.java