@Override
    public boolean performLivenessCheck() throws Exception {
        final String url = config.getLivenessCheckUrl();
        boolean isLive;

        if (NullSafe.isNonBlankString(url)) {
            final HttpGet httpGet = new HttpGet(url);
            httpGet.addHeader("User-Agent", userAgent);
            addAuthHeaders(httpGet);

            try {
                final int responseCode = httpClient.execute(httpGet, response -> {
                    final int code = response.getCode();
                    LOGGER.debug("Liveness check, code: {}, response: '{}'", code, response);
                    consumeAndCloseResponseContent(response);
                    return code;
                });

                isLive = responseCode == HttpStatus.SC_OK;
                if (!isLive) {
                    throw new Exception(LogUtil.message("Got response code {} from livenessCheckUrl '{}'",
                            responseCode, url));
                }
            } catch (IOException e) {
                final String msg = LogUtil.message("Error calling livenessCheckUrl '{}': {}",
                        url, LogUtil.exceptionMessage(e));
                LOGGER.debug(msg, e);
                // Consider it not live
                throw new Exception(msg, e);
            }
        } else {
            isLive = true;
        }
        return isLive;
    }
Handler class that forwards the request to a URL.
stroom-proxy/stroom-proxy-app/src/main/java/stroom/proxy/app/handler/HttpSender.java