Here you can find the source of sleep(long milliseconds)
public static void sleep(long milliseconds)
//package com.java2s; /*//from w w w . j a va2s . c om * Copyright 2016-2017 The OpenTracing 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.Random; import java.util.concurrent.TimeUnit; public class Main { public static void sleep() { try { TimeUnit.MILLISECONDS.sleep(new Random().nextInt(2000)); } catch (InterruptedException e) { e.printStackTrace(); Thread.currentThread().interrupt(); } } public static void sleep(long milliseconds) { try { TimeUnit.MILLISECONDS.sleep(milliseconds); } catch (InterruptedException e) { e.printStackTrace(); Thread.currentThread().interrupt(); } } }