Here you can find the source of daysBetween(Calendar startDate, Calendar endDate)
protected static long daysBetween(Calendar startDate, Calendar endDate)
//package com.java2s; /**/*ww w.ja v a 2 s . c o m*/ * Copyright (c) 2015 The original author or authors * <p> * 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 * <p> * http://www.apache.org/licenses/LICENSE-2.0 * <p> * 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.*; import java.util.concurrent.TimeUnit; public class Main { protected static long daysBetween(Calendar startDate, Calendar endDate) { long end = endDate.getTimeInMillis(); long start = startDate.getTimeInMillis(); return TimeUnit.MILLISECONDS.toDays(Math.abs(end - start)); } }