code: public String getProperty(String name)
    {
      Params.notNullOrEmpty(name, "Property name");
      usedProperties.add(name);
      return properties.getProperty(name);
    }
docs: Get configuration object property value or null if there is no property with requested name.
  
  @param name property name.
  @return configuration object property value or null.
  @throws IllegalArgumentException if <code>name</code> argument is null or empty.