Regex to find any characters failing

I keep getting nullpointerexception for this code.

Just want to determine if string has any characters A-Z and return false, else return true. What am I doing wrong?

Note data = "A2"

public static boolean calculable(String data) {
        Pattern p = Pattern.compile("[A-Z]");
        Matcher m = p.matcher(data);
        if (m.find()) {

            return false;
        }

        return true;
    }