src/java.base/share/classes/java/lang/ref/Cleaner.java

@@ -219,10 +219,20 @@
         Objects.requireNonNull(action, "action");
         return new CleanerImpl.PhantomCleanableRef(obj, this, action);
     }
 
     /**
+     * Processes next Cleanable that has been waiting in the queue.
+     *
+     * @return {@code true} if a Cleanable was found in the queue and
+     * was processed or {@code false} if the queue was empty.
+     */
+    boolean cleanNextEnqueued() {
+        return impl.cleanNextEnqueued();
+    }
+
+    /**
      * {@code Cleanable} represents an object and a
      * cleaning action registered in a {@code Cleaner}.
      * @since 9
      */
     public interface Cleanable {