code: public void mergeProperties(@NotNull final InputStream stream) throws IOException {
          props.load(stream);
          logProperties("Properties updated via merge", props);
      }
docs: Merges a new properties file into the current properties. This method
  allows for the loading of a user provided properties file.<br><br>
  <b>Note</b>: even if using this method - system properties will be loaded
  before properties loaded from files.
  
  @param stream an Input Stream pointing at a properties file to merge
  @throws java.io.IOException is thrown when there is an exception
  loading/merging the properties