Destroys this thread group and all of its subgroups. This thread
group must be empty, indicating that all threads that had been in
this thread group have since stopped.
<p>
First, the {@code checkAccess} method of this thread group is
called with no arguments; this may result in a security exception.
@throws IllegalThreadStateException if the thread group is not
empty or if the thread group has already been destroyed.
@throws SecurityException if the current thread cannot modify this
thread group.
@see java.lang.ThreadGroupEx#checkAccess()
Destroys this thread group and all of its subgroups. This thread group must be empty, indicating that all threads that had been in this thread group have since stopped. <p> First, the {@code checkAccess} method of this thread group is called with no arguments; this may result in a security exception.
@throws IllegalThreadStateException if the thread group is not empty or if the thread group has already been destroyed. @throws SecurityException if the current thread cannot modify this thread group. @see java.lang.ThreadGroupEx#checkAccess()