Here you can find the source of decrementWheelsCount()
public static void decrementWheelsCount()
//package com.java2s; /*/*from w ww . j a v a2 s .c om*/ * Copyright 2016 Dmitry Spikhalskiy. All Rights Reserved. * * 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. * limitations under the License. */ import java.util.concurrent.atomic.AtomicInteger; public class Main { private final static AtomicInteger activeFutures = new AtomicInteger(); public static void decrementWheelsCount() { synchronized (activeFutures) { activeFutures.incrementAndGet(); activeFutures.notify(); } } }