Here you can find the source of toUtcDay(Date d)
public static String toUtcDay(Date d)
//package com.java2s; /**/* ww w. j a v a 2 s.c o m*/ * Copyright 2009, 2010 The Regents of the University of California * Licensed under the Educational Community 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.osedu.org/licenses/ECL-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.text.DateFormat; import java.text.SimpleDateFormat; import java.util.Date; import java.util.TimeZone; public class Main { /** * Convert to a UTC date string containing only the day (granularity is "day"). */ public static String toUtcDay(Date d) { return newDateFormat().format(d); } public static DateFormat newDateFormat() { SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd"); f.setTimeZone(TimeZone.getTimeZone("UTC")); return f; } }