code: public void setValue(Object value)
    {
      if(value instanceof String) {
        Params.notEmpty((String)value, "Value");
        this.value = (String)value;
      }
      else {
        this.value = value != null ? converter.asString(value) : null;
      }
    }
docs: Set this configuration object value. Value is converter to string before store it. If <code>value</code> argument
  is null this setter will reset this configuration object value.
  
  @param value value to set, null accepted.
  @throws IllegalArgumentException if <code>value</code> argument is an empty string.
  @throws ConverterException if there is no converter registered for value type.