Here you can find the source of getAge(Date birthDay)
public static int getAge(Date birthDay)
//package com.java2s; //License from project: Apache License import java.util.Calendar; import java.util.Date; public class Main { public static int getAge(Date birthDay) { Calendar cal = Calendar.getInstance(); int yearNow = cal.get(Calendar.YEAR); int monthNow = cal.get(Calendar.MONTH) + 1; int dayOfMonthNow = cal.get(Calendar.DAY_OF_MONTH); cal.setTime(birthDay);//from w ww . ja v a 2 s . c om int yearBirth = cal.get(Calendar.YEAR); int monthBirth = cal.get(Calendar.MONTH); int dayOfMonthBirth = cal.get(Calendar.DAY_OF_MONTH); int age = yearNow - yearBirth; if (monthNow <= monthBirth) { if (monthNow == monthBirth) { if (dayOfMonthNow < dayOfMonthBirth) { age--; } } else { age--; } } return age; } }