Here you can find the source of calcDifferenceAsYearsPrivate(Calendar aBaseDate, Calendar aTargetDate)
private static int calcDifferenceAsYearsPrivate(Calendar aBaseDate, Calendar aTargetDate)
//package com.java2s; /*//from ww w . j a v a 2s. co m * Copyright 2012 Hiromasa Horiguchi ( The University of Tokyo ) * * 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.Calendar; public class Main { private static int calcDifferenceAsYearsPrivate(Calendar aBaseDate, Calendar aTargetDate) { int tBaseDateMonth = aBaseDate.get(Calendar.MONTH); int tTargetDateMonth = aTargetDate.get(Calendar.MONTH); return aTargetDate.get(Calendar.YEAR) - aBaseDate.get(Calendar.YEAR) - (tBaseDateMonth > tTargetDateMonth || (tBaseDateMonth == tTargetDateMonth && aBaseDate.get(Calendar.DATE) > aTargetDate.get(Calendar.DATE)) ? 1 : 0); } }