--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/lang/ref/ReferenceEnqueue.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2011, 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+ * @bug 4268317 8132306 8175797
+ * @summary Test if Reference.enqueue() works properly with GC
+ * @run main ReferenceEnqueue
+ * @run main/othervm -Djdk.lang.ref.disableClearBeforeEnqueue=true ReferenceEnqueue
+ */
+
+import java.lang.ref.*;
+import java.util.ArrayList;
+import java.util.List;
+
+public class ReferenceEnqueue {
+
+    public static void main(String args[]) throws Exception {
+        for (int i=0; i < 5; i++) {
+            new WeakRef().run();
+            new ExplicitEnqueue().run();
+        }
+        System.out.println("Test passed.");
+    }
+
+    static class WeakRef {
+        final ReferenceQueue<Object> queue = new ReferenceQueue<Object>();
+        final Reference<Object> ref;
+        final int iterations = 1000;
+
+        WeakRef() {
+            this.ref = new WeakReference<Object>(new Object(), queue);
+        }
+
+        void run() throws InterruptedException {
+            System.gc();
+            for (int i = 0; i < iterations; i++) {
+                System.gc();
+                if (ref.isEnqueued()) {
+                    break;
+                }
+
+                Thread.sleep(100);
+            }
+
+            if (ref.isEnqueued() == false) {
+                // GC have not enqueued refWeak for the timeout period
+                System.out.println("Reference not enqueued yet");
+                return;
+            }
+
+            if (ref.enqueue() == true) {
+                // enqueue() should return false since
+                // ref is already enqueued by the GC
+                throw new RuntimeException("Error: enqueue() returned true;"
+                        + " expected false");
+            }
+
+            if (queue.poll() == null) {
+                // poll() should return ref enqueued by the GC
+                throw new RuntimeException("Error: poll() returned null;"
+                        + " expected ref object");
+            }
+        }
+    }
+
+    static class ExplicitEnqueue {
+        final ReferenceQueue<Object> queue = new ReferenceQueue<>();
+        final List<Reference<Object>> refs = new ArrayList<>();
+        final int iterations = 1000;
+        final boolean disableClearBeforeEnqueue =
+            Boolean.getBoolean("jdk.lang.ref.disableClearBeforeEnqueue");
+
+        ExplicitEnqueue() {
+            this.refs.add(new SoftReference<>(new Object(), queue));
+            this.refs.add(new WeakReference<>(new Object(), queue));
+            // Can't test PhantomReference because get() always returns null.
+        }
+
+        void run() throws InterruptedException {
+            for (Reference<Object> ref : refs) {
+                if (ref.enqueue() == false) {
+                    throw new RuntimeException("Error: enqueue failed");
+                }
+                if (disableClearBeforeEnqueue && ref.get() == null) {
+                    throw new RuntimeException("Error: clearing should be disabled");
+                }
+                if (!disableClearBeforeEnqueue && ref.get() != null) {
+                    throw new RuntimeException("Error: referent must be cleared");
+                }
+            }
+
+            System.gc();
+            for (int i = 0; refs.size() > 0 && i < iterations; i++) {
+                Reference<Object> ref = (Reference<Object>)queue.poll();
+                if (ref == null) {
+                    System.gc();
+                    Thread.sleep(100);
+                    continue;
+                }
+
+                if (refs.remove(ref) == false) {
+                    throw new RuntimeException("Error: unknown reference " + ref);
+                }
+            }
+
+            if (!refs.isEmpty()) {
+                throw new RuntimeException("Error: not all references are removed");
+            }
+        }
+    }
+}