code: private String findAgentUrl(Configuration pConfig) {
          // System property has precedence
          String url = System.getProperty("jolokia." + ConfigKey.DISCOVERY_AGENT_URL.getKeyValue());
          if (url == null) {
              url = System.getenv("JOLOKIA_DISCOVERY_AGENT_URL");
              if (url == null) {
                  url = pConfig.get(ConfigKey.DISCOVERY_AGENT_URL);
              }
          }
          return NetworkUtil.replaceExpression(url);
      }
docs: Try to find an URL for system props or config