/**
* 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</code> method of this thread group is called with no arguments;
* this may result in a security exception.
*
* @exception IllegalThreadStateException if the thread group is not empty or if the thread group
* has already been destroyed.
* @exception SecurityException if the current thread cannot modify this thread group.
* @see java.lang.ThreadGroup#checkAccess()
* @since JDK1.0
*/
public final void destroy() {
int ngroupsSnapshot;
ThreadGroup[] groupsSnapshot;
synchronized (this) {
checkAccess();
if (destroyed || (nthreads > 0)) {
throw new IllegalThreadStateException();
}
ngroupsSnapshot = ngroups;
if (groups != null) {
groupsSnapshot = new ThreadGroup[ngroupsSnapshot];
System.arraycopy(groups, 0, groupsSnapshot, 0, ngroupsSnapshot);
} else {
groupsSnapshot = null;
}
if (parent != null) {
destroyed = true;
ngroups = 0;
groups = null;
nthreads = 0;
threads = null;
}
}
for (int i = 0; i < ngroupsSnapshot; i += 1) {
groupsSnapshot[i].destroy();
}
if (parent != null) {
parent.remove(this);
}
}
