Here you can find the source of sleep(long millions)
@SuppressWarnings("static-access") public static void sleep(long millions)
//package com.java2s; //License from project: Apache License public class Main { @SuppressWarnings("static-access") public static void sleep(long millions) { try {/*from w w w .j a v a 2s. c o m*/ Thread.currentThread().sleep(millions); } catch (InterruptedException e) { e.printStackTrace(); } } }