Java ThreadGroup getParent()方法

ThreadGroup類的getParent()方法返回線程組的父級。

語法

public final ThreadGroup getParent()

返回

此方法返回線程組的父級。

異常

• SecurityException：如果當前線程無法修改線程組。

示例

class NewThread extends Thread
{
    NewThread(String threadname, ThreadGroup tg)
    {
        super(tg, threadname);
    }
    public void run()
    {
        for(int i = 0;i < 10;i++)
        {
            i++;
        }
        System.out.println(Thread.currentThread().getName() + " completed executing");
    }
}
public class ThreadGroupGetParentExp
{
    public static void main(String arg[]) throws InterruptedException,
        SecurityException, Exception
    {
        // creating a parent threadGroup
        ThreadGroup tg1 = new ThreadGroup("Parent thread");
        // creating a child threadGroup
        ThreadGroup tg2 = new ThreadGroup(tg1, "Child thread");

        // creating a thread
        NewThread t1 = new NewThread("Thread-1", tg1);
        System.out.println("Starting Thread-1");
        t1.start();

       // creating another thread
        NewThread t2 = new NewThread("Thread-2", tg2);
        System.out.println("Starting Thread-2");
        t2.start();

        // print the parentThreadGroup of parent thread
        System.out.println("ParentThreadGroup for " +
            tg1.getName() + " is " + tg1.getParent().getName());
        // print the parentThreadGroup of child thread
        System.out.println("ParentThreadGroup for " +
            tg2.getName() + " is " + tg2.getParent().getName());
    }
}

執行上面示例代碼，得到以下結果：

Starting Thread-1
Starting Thread-2
ParentThreadGroup for Parent thread is main
ParentThreadGroup for Child thread is Parent thread
Thread-1 completed executing
Thread-2 completed executing