双检索单例模式

双检索单例模式

/**
 * 双检索单例模式
 * 描述: TODO
 *
 * @author lyn
 * @date 2022/3/2 17:16
 */
public class SingleBean {
    private static volatile SingleBean instance;
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    private SingleBean() {
    }
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    public static SingleBean getInstance() {
        if (instance == null) {
            synchronized (SingleBean.class) {
                if (instance == null) {
                    instance = new SingleBean();
                }
            }
        }
        return instance;
    }
}