Here you can find the source of timestampMillis()
public static String timestampMillis()
//package com.java2s; /**/*ww w .j av a2 s .c om*/ * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.concurrent.TimeUnit; public class Main { public static String timestampMillis() { long now = System.currentTimeMillis(); long secs = TimeUnit.MILLISECONDS.toSeconds(now); long msecs = now - TimeUnit.SECONDS.toMillis(secs); return String.format("%d.%03d", secs, msecs); } }