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AtomicityTest.java
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45 lines (38 loc) · 1.07 KB
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package Thread.Basic;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
/*
* 用synchronize来修复程序，证明其实安全的
* */
public class AtomicityTest implements Runnable{
private volatile int i=0;
//return i是原子性的操作，但是缺少同步使其数值在不稳定的中间状态被获取
public synchronized int getValue(){
return i;
}
//此方法肯定是要同步的
//i++是非原子性的操作，因此要将i设为volatile域，每次增加都刷新到内存中，保证可视性
private synchronized void evenIncrement(){
i++;
i++;
}
public void run() {
while(true){
evenIncrement();
}
}
public static void main(String[] args) {
ExecutorService executorService=Executors.newCachedThreadPool();
AtomicityTest auTest=new AtomicityTest();
executorService.execute(auTest);
while(true){
int val=auTest.getValue();
System.out.println(val);
//如果上面运行正确的话，不可能出现奇数
if(val%2!=0){
System.out.println(val);
System.exit(0);
}
}
}
}