public synchronized AlphabeticIndex addLabels(Locale locale){
  addLabels(peer,locale.toString());
  return this;
}

public synchronized AlphabeticIndex addLabels ( Locale locale ) { addLabels ( peer , locale . toString ( ) ) ; return this ; }
adds the index characters from the given locale to the index . the labels are added to those that are already in the index ; they do not replace the existing index characters . the collation order for this index is not changed ; it remains that of the locale that was originally specified when creating this index .
