import java.util.Collections;
import java.util.Iterator;
import java.util.Queue;
+import org.opendaylight.yangtools.concepts.Immutable;
/**
* A specialized always-empty implementation of {@link java.util.Queue}. This implementation will always refuse new
*/
// TODO: move this class into yangtools.util
@Beta
-public final class EmptyQueue<E> extends AbstractQueue<E> {
+public final class EmptyQueue<E> extends AbstractQueue<E> implements Immutable {
private static final EmptyQueue<?> INSTANCE = new EmptyQueue<>();
private EmptyQueue() {