Java线程组checkAccess()方法
ThreadGroup类的
activeCount()方法确定当前正在运行的线程是否有权修改线程组。
语法
public final void checkAccess()
返回
它不返回任何值。
异常
SecurityException : 如果不允许当前线程访问线程组，则会引发此异常。
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 ThreadGroupCkeckAccessExp
{
public static void main(String arg[]) throws InterruptedException, SecurityException
{
// creating a ThreadGroup
ThreadGroup g1 = new ThreadGroup("Parent thread");
// creating a child ThreadGroup for parent ThreadGroup
ThreadGroup g2 = new ThreadGroup(g1, "child thread");
// creating a thread
NewThread t1 = new NewThread("Thread-1", g1);
t1.start();
// creating another thread
NewThread t2 = new NewThread("Thread-2", g1);
t2.start();
// Check for access permission of current running thread
g1.checkAccess();
System.out.println(g1.getName() + " has access");
g2.checkAccess();
System.out.println(g2.getName() + " has access");
}
}
输出:
Parent thread has access
child thread has access
Thread-1 finished executing
Thread-2 finished executing
