code: public final void put(final String key, final String value) {
          final Property prop = find(key);
          if (prop == null) {
              props.add(new Property(key, null, value));
          } else {
              prop.setValue(value);
          }
      }
docs: Set a value for a property. If a property with the key is already known the value will be changed. Otherwise a new property will be
  created.
  
  @param key
  Key to set.
  @param value
  Value to set.