code: static void loadHadoopClustersProps(String filename) {
      // read the property file
      // populate the map
      Properties prop = new Properties();
      if (StringUtils.isBlank(filename)) {
        filename = Constants.HRAVEN_CLUSTER_PROPERTIES_FILENAME;
      }
      try {
        //TODO : property file to be moved out from resources into config dir
        InputStream inp = Cluster.class.getResourceAsStream("/" + filename);
        if (inp == null) {
          LOG.error(filename
              + " for mapping clusters to cluster identifiers in hRaven does not exist");
          return;
        }
        prop.load(inp);
        Set<String> hostnames = prop.stringPropertyNames();
        for (String h : hostnames) {
          CLUSTERS_BY_HOST.put(h, prop.getProperty(h));
        }
      } catch (IOException e) {
        // An ExceptionInInitializerError will be thrown to indicate that an
        // exception occurred during evaluation of a static initializer or the
        // initializer for a static variable.
        throw new ExceptionInInitializerError(" Could not load properties file " + filename
            + " for mapping clusters to cluster identifiers in hRaven");
      }
    }
docs: testing with different properties file names