@NotNull public static String capitalize(@NotNull String s){
  return s.isEmpty() ? s : (toUpperCase(s.charAt(0)) + s.substring(1));
}

@ NotNull public static String capitalize ( @ NotNull String s ) { return s . isEmpty ( ) ? s : ( toUpperCase ( s . charAt ( 0 ) ) + s . substring ( 1 ) ) ; }
returns given string with its first letter in uppercase .
