- 非线程安全
package com.zuche.thread.demo1;
public class TestClient { public static void main(String[] args) { final Account account = new Account(1000); Thread t = new Thread(new Runnable(){ public void run() { account.add(20); } }); Thread t1 = new Thread(new Runnable(){ public void run() { account.withdraw(20); } }); t.start(); t1.start(); System.out.println("最后的金额:" + account.getBalance()); } } 理论上最后的金额应该为1000
- 死锁
public class WorkThread extends Thread{ private String adjustMoney = "adjustMoney"; private String work = "work"; private String ruleType; public WorkThread(String ruleType){ this.ruleType = ruleType; } public void run(){ if(ruleType.equals("employee")){ employeeSay(); } if(ruleType.equals("boss")){ bossSay(); } } private void employeeSay(){ synchronized(adjustMoney){ System.out.println("员工说,先调薪后干活"); synchronized (work) { System.out.println("员工调薪顺利调薪,开始带劲的干活"); } } } private void bossSay(){ synchronized(work){ System.out.println("老板说,先给我好好的干活再来谈加薪的事儿"); synchronized(adjustMoney){ System.out.println("活干的不错,可以适当的考虑加点钱"); } } } } 运行后,程序不能正常退出,卡死在那儿。 死锁概念: 2个线程相互僵持不下,导致无法访问共享资源,最终无法释放锁资源。
- 饥饿锁
public class Toilet{ public synchronized void doStaff(){ System.out.println(Thread.currentThread().getName() + " begin."); clean(); while(true){ System.out.println(Thread.currentThread().getName() + " doing."); try { Thread.sleep(2000L); } catch (InterruptedException e) { e.printStackTrace(); } } } private void clean(){ } } 运行后,另一个线程无法访问共享资源 饥饿锁概念: 一个线程占用着锁不放导致其它线程无法访问共享资源