protected Collection<String> excludedExtensionsFromByteCounts(){
  return new HashSet<String>(Arrays.asList(new String[]{"si","lock"}));
}

protected Collection < String > excludedExtensionsFromByteCounts ( ) { return new HashSet < String > ( Arrays . asList ( new String [ ] { "si" , "lock" } ) ) ; }
return the list of extensions that should be excluded from byte counts when comparing indices that store the same content .
