code: public static Config loadConfig(Reader configReader, boolean useSystemEnvironment) {
          return loadConfig(ConfigParseOptions.defaults(),
                  ConfigResolveOptions.defaults().setUseSystemEnvironment(useSystemEnvironment),
                  configReader);
      }
docs: Load, Parse & Resolve configurations from a reader, with default parse & resolve options.
  
  @param configReader
  @param useSystemEnvironment
  {@code true} to resolve substitutions falling back to environment
  variables
  @return