code: public static Long getLongProperty(String property) {
          if (property == null) {
              return null;
          }
          Long propertyLong = null;
          try {
              propertyLong = Long.valueOf(property);
          } catch (NumberFormatException e) {
              LOG.warn("Cannot convert string value into number", e);
          }
          return propertyLong;
      }
docs: Get a long property from properties.
  
  @param property the property as string
  @return The property as long or null if could not convert