boolean ping(int maxAttempts, int startTimeout) {
        checkArgument(maxAttempts >= 1);
        checkArgument(startTimeout > 0);

        int timeout = startTimeout;
        int attempts = 0;
        while (attempts < maxAttempts) {
            try {
                Future<Boolean> pingFuture = pingExecutor.submit(new PingCallable());
                boolean pinged = pingFuture.get(timeout, MILLISECONDS);
                if (pinged) {
                    return true;
                }
            } catch (TimeoutException e) {
                Logger.warn("Error pinging server (attempt: " + attempts + ", timeout: " + timeout + "). ");
            } catch (InterruptedException | ExecutionException e) {
                Logger.error("Error pinging server due to unexpected error");
            }
            attempts++;
            timeout *= 2;
        }
        String error = String.format(Locale.US, "Error pinging server (attempts: %d, max timeout: %d). " +
                        "If you see this message, please, report at https://github.com/danikula/AndroidVideoCache/issues/134. " +
                        "Default proxies are: %s"
                , attempts, timeout / 2, getDefaultProxies());
        Logger.error(error);
        return false;
    }
Pings {@link HttpProxyCacheServer} to make sure it works.
VideoCache/src/main/java/com/yc/videocache/Pinger.java