import java.lang.ref.PhantomReference;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
public class Main {
public static void main(String[] argv) throws Exception {
ReferenceQueue rq = new ReferenceQueue();
PhantomReference pr = new PhantomReference("object", rq);
while (true) {
Reference r = rq.remove();
if (r == pr) {
// about to be reclaimed.
r.clear();
}
}
}
}