private static final boolean isSupplementary(int ch){
  return ch >= Character.MIN_SUPPLEMENTARY_CODE_POINT || Character.isSurrogate((char)ch);
}

private static final boolean isSupplementary ( int ch ) { return ch >= Character . MIN_SUPPLEMENTARY_CODE_POINT || Character . isSurrogate ( ( char ) ch ) ; }
determines if the specified code point is a supplementary character or unpaired surrogate .
