code: 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;
      }
docs: returns true if the input string has letters and they are all UPPERCASE
  
  @param str
  @return