Java：获取当前线程组的父线程组

下面的代码中，先获取了当前线程所在的线程组，然后获得了父线程组：

package com.thb;

public class Test5 {

    public static void main(String[] args) {
       ThreadGroup currentThreadGroup = Thread.currentThread().getThreadGroup();
       ThreadGroup parentThreadGroup = currentThreadGroup.getParent();
       System.out.println("current thread group: "+ currentThreadGroup);
       System.out.println("parent thread group: "+ parentThreadGroup);
    }

}

运行输出：