Java tutorial
//package com.java2s; import java.util.Calendar; import java.util.TimeZone; public class Main { public static long getDayInUTC(long time) { Calendar cal = Calendar.getInstance(); cal.setTimeInMillis(time); cal.set(Calendar.HOUR, 0); cal.set(Calendar.MINUTE, 0); cal.set(Calendar.SECOND, 0); cal.set(Calendar.MILLISECOND, 0); cal.setTimeZone(TimeZone.getTimeZone("UTC")); return cal.getTimeInMillis(); } }