code: public static String getSystemProperty(String name, String defaultValue) {
          String value;
          value = System.getProperty(name, null);
          if (value != null) {
              return value;
          }
          value = System.getenv(name);
          if (value != null) {
              return value;
          }
          return defaultValue;
      }
docs: Replies the value of the system property.
  
  @param name
  - name of the property.
  @param defaultValue
  - value to reply if the these is no property found
  @return the value, or defaultValue.