Here you can find the source of getDiffInMonths(Date firstDate, Date lastDate)
public static int getDiffInMonths(Date firstDate, Date lastDate)
//package com.java2s; /*/*from w ww . j a v a 2s . c om*/ Copyright (C) 2012 The Stanford MobiSocial Laboratory Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ import java.util.*; public class Main { public static int getDiffInMonths(Date firstDate, Date lastDate) { Calendar cFirst = new GregorianCalendar(); cFirst.setTime(firstDate); Calendar cLast = new GregorianCalendar(); cLast.setTime(lastDate); int cFirst_year = cFirst.get(Calendar.YEAR); int cFirst_month = cFirst.get(Calendar.MONTH); int cLast_year = cLast.get(Calendar.YEAR); int cLast_month = cLast.get(Calendar.MONTH); return (cLast_year - cFirst_year) * (cLast.getMaximum(Calendar.MONTH) - cLast.getMinimum(Calendar.MONTH) + 1) + (cLast_month - cFirst_month); } }