Java ThreadGroup activeCount()用法及代码示例

ThreadGroup 类的 activeCount() 方法用于返回当前线程的线程组中的活动线程数。返回值只是一个估计值，因为在此方法遍历内部数据结构时，线程数可能会动态变化。

用法

public static int activeCount()

它返回当前线程的线程组中的活动线程数。

示例

class NewThread extends Thread 
{
    NewThread(String threadname, ThreadGroup tg)
    {
        super(tg, threadname);
    }
    public void run()
    {
        for (int i = 0; i < 10; i++) 
        {
            try
            {
                Thread.sleep(10);
            }
            catch (InterruptedException ex) 
            {
              System.out.println(Thread.currentThread().getName() + " interrupted");
            }
        }
        System.out.println(Thread.currentThread().getName() + " completed executing");
    }
} 
public class ThreadGroupActiveCountExp
{
    public static void main(String arg[])
    {
        // creating the thread group
        ThreadGroup tg1 = new ThreadGroup("parent thread group");

        // creating the threads
        NewThread t1 = new NewThread("Thread-1", tg1);
        NewThread t2 = new NewThread("Thread-2", tg1);
        NewThread t3 = new NewThread("Thread-3", tg1);
        
        // this will call the run() method
        t1.start();
        t2.start();
        t3.start();

        // checking the number of active thread
        System.out.println("Number of active thread:"+ tg1.activeCount());
    }
}

输出：

Number of active thread:3
Thread-1 completed executing
Thread-2 completed executing
Thread-3 completed executing

相关用法

注：本文由纯净天空筛选整理自 Java ThreadGroup activeCount() method。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。