How do I calculate someone's age in Java?

Question

I want to return an age in years as an int in a Java method. What I have now is the following where getBirthDate() returns a Date object (with the birth date ;-)):

Answer 1

Easiest way without any libraries:

    long today = new Date().getTime();
    long diff = today - birth;
    long age = diff / DateUtils.YEAR_IN_MILLIS;