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import java.io.IOException;
import java.lang.reflect.Field;
import java.util.HashSet;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * -XX:+PrintGCDetails
 * jcmd PID GC.run 强制来一发GC.
 */

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# JCStress repo, version 0.5
hg clone http://hg.openjdk.java.net/code-tools/jcstress/ jcstress
cd jcstress
hg up 0.5

# 1) jcstress-sample
# source code: http://hg.openjdk.java.net/code-tools/jcstress/file/3c94746a6abf/jcstress-samples/src/main/java/org/openjdk/jcstress/samples
# JMM & Concurrent samples also on: https://gist.github.com/liufor/f08495f0596ddf98a3542307b72f080f
# maven: https://mvnrepository.com/artifact/org.openjdk.jcstress/jcstress-samples

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/*
 * Copyright (c) 2016, Red Hat Inc.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *

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/**
 * 简单例子验证 volatile 的，不用JCStress.
 */
public class SyncDeadLock {

    public static void main(String[] args) {

        DataRace dataRace = new DataRace();

        Thread[] threads = new Thread[100];

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import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

@Inherited
@Retention(RetentionPolicy.RUNTIME)
public @interface AnnotationX {
}

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public class Sync implements Runnable {
        int n;

        public static void main(String[] args) {
                Sync sync = new Sync();
                new Thread(sync, "Sync1").start();
                new Thread(sync, "Sync2").start();
                new Thread(sync, "Sync3").start();
        }

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import io.undertow.*;
import io.undertow.server.*;
import io.undertow.util.*;

public class HelloWorldServer {

        public static void main(final String[] args) {
                Undertow server = Undertow.builder()
                        .addHttpListener(8080, "localhost")
                        .setHandler(new HttpHandler() {

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import jdk.nashorn.internal.runtime.ECMAException;
import sun.misc.Launcher;
import sun.misc.URLClassPath;

import java.lang.reflect.Field;
import java.net.URL;
import java.net.URLClassLoader;

/**
 * 简单打印出 Boot、System、Ext 3个 classloader 的 对应的 classpath 的 URLs.

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public class LocalVariablesPrimitiveTypeLiteralBytecodeDemo {

    public static void main(String[] args) throws InterruptedException {

        boolean booltrue = true;  //ICONST_1
        boolean boolfalse = false; //ICONST_0


        //byte、short、char、int 局部变量根据值大小不同而由不同的
        //byte 范围        [-128,127]，        ICONST_X 、BIPUSH

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data 1879
database 1245
system 1196
write 976
node 751
page 744
example 663
time 600
need 586
read 566