Here you can find the source of setDayStart(final Date date)
public static Date setDayStart(final Date date)
//package com.java2s; /*//from www. j a v a 2 s. c o m * Copyright 2016-2017 the original author or authors. * * 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; import java.util.Date; public class Main { public static Date setDayStart(final Date date) { final Calendar c = Calendar.getInstance(); c.setLenient(false); c.setTime(date); c.set(Calendar.HOUR_OF_DAY, 0); c.set(Calendar.MINUTE, 0); c.set(Calendar.SECOND, 0); return c.getTime(); } }