public static boolean isAllUpperCase(String str){
  if (str == null)   return false;
  boolean hasLetters=false;
  char c;
  for (int i=str.length() - 1; i >= 0; i--) {
    c=str.charAt(i);
    if (Character.isLetter(c)) {
      if (!Character.isUpperCase(c))       return false;
      hasLetters=true;
    }
  }
  return hasLetters;
}

public static boolean isAllUpperCase ( String str ) { if ( str == null ) return false ; boolean hasLetters = false ; char c ; for ( int i = str . length ( ) - 1 ; i >= 0 ; i -- ) { c = str . charAt ( i ) ; if ( Character . isLetter ( c ) ) { if ( ! Character . isUpperCase ( c ) ) return false ; hasLetters = true ; } } return hasLetters ; }
returns true if the input string has letters and they are all uppercase
