code: public String put(final String key, String value) {
          if (key == null || initProps == null)
              return null;
  
          return initProps.put(key, value);
      }
docs: Set new property into set of initial properties. No effect (and returns
  null) if key is null.
  
  @param key
  Property key string
  @param value
  Property value object
  @return current/replaced value