public static String suffix_s(final String noun){
  final char last=Character.toLowerCase(noun.charAt(noun.length() - 1));
  if (last == 's') {
    return noun + "'";
  }
  return noun + "'s";
}

public static String suffix_s ( final String noun ) { final char last = Character . toLowerCase ( noun . charAt ( noun . length ( ) - 1 ) ) ; if ( last == 's' ) { return noun + "'" ; } return noun + "'s" ; }
" [ noun ] ' s " or " [ noun ] ' " , depending on the last character .
