ElasticStack高级开发与架构2023\/--》ccys1473
以下内容忽略
4、static + private + getInstance + instance + synchronized(对象锁)缩小锁代码,但不安全
package Sigleton;
public class T04 {
private static T04 t04;
public static T04 getInstance(){
if(t04 == null){
synchronized (T04.class){
try {
Thread.sleep(2);
}catch (Exception e){
}
t04 = new T04();
}
}
return t04;
}
public static void main(String[] args){
for(int i=0;i<20;i++){
new Thread(new Runnable() {
@Override
public void run() {
System.out.println(T04.getInstance().hashCode());
}
}).start();
}
}
}
