--- old/src/java.base/share/classes/java/lang/ref/Finalizer.java	2015-05-14 09:44:15.211836252 +0200
+++ new/src/java.base/share/classes/java/lang/ref/Finalizer.java	2015-05-14 09:44:15.162836173 +0200
@@ -27,6 +27,10 @@
 
 import java.security.PrivilegedAction;
 import java.security.AccessController;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
 import sun.misc.JavaLangAccess;
 import sun.misc.ManagedLocalsThread;
 import sun.misc.SharedSecrets;
@@ -186,6 +190,32 @@
                 }}});
     }
 
+    static String printFinalizationQueue() {
+        Map<String, int[]> countMap = new HashMap<>();
+        queue.forEach(r -> {
+            Object referent = r.get();
+            if (referent != null) {
+                countMap.computeIfAbsent(
+                    referent.getClass().getName(), k -> new int[1])[0]++;
+                /* Clear stack slot containing this variable, to decrease
+                   the chances of false retention with a conservative GC */
+                referent = null;
+            }
+        });
+        @SuppressWarnings("unchecked")
+        Map.Entry<String, int[]>[] entries = countMap.entrySet().toArray(
+            new Map.Entry[countMap.size()]
+        );
+        Arrays.sort(entries, (e1, e2) ->
+            Integer.compare(e2.getValue()[0], e1.getValue()[0]));
+        StringBuilder sb = new StringBuilder();
+        for (Map.Entry<String, int[]> e : entries) {
+            sb.append("Class: ").append(e.getKey())
+              .append(" count: ").append(e.getValue()[0]).append("\n");
+        }
+        return sb.toString();
+    }
+
     private static class FinalizerThread extends ManagedLocalsThread {
         private volatile boolean running;
         FinalizerThread(ThreadGroup g) {
--- old/src/java.base/share/classes/java/lang/ref/ReferenceQueue.java	2015-05-14 09:44:15.402836559 +0200
+++ new/src/java.base/share/classes/java/lang/ref/ReferenceQueue.java	2015-05-14 09:44:15.353836480 +0200
@@ -25,6 +25,9 @@
 
 package java.lang.ref;
 
+import sun.misc.Unsafe;
+import java.util.function.Consumer;
+
 /**
  * Reference queues, to which registered reference objects are appended by the
  * garbage collector after the appropriate reachability changes are detected.
@@ -83,6 +86,10 @@
                 null :
                 r.next; // Unchecked due to the next field having a raw type in Reference
             r.queue = NULL;
+            // make sure the store to r.next below doesn't float up
+            // before the store to r.queue above because we need this
+            // for correct lock-less iteration in forEach()
+            U.storeFence();
             r.next = r;
             queueLength--;
             if (r instanceof FinalReference) {
@@ -164,4 +171,38 @@
         return remove(0);
     }
 
+    /**
+     * Iterate queue and invoke given action with each Reference.
+     * Suitable for diagnostic purposes.
+     * WARNING: any use of this method should make sure to not
+     * retain the referents of iterated references (in case of
+     * FinalReference(s)) so that their life is not prolonged more
+     * than necessary.
+     */
+    void forEach(Consumer<? super Reference<? extends T>> action) {
+        for (Reference<? extends T> r = head; r != null;) {
+            action.accept(r);
+            Reference rn = r.next;
+            // make sure load of r.queue below doesn't float up before
+            // the load of r.next above. The corresponding stores are
+            // performed in reallyPoll() in reverse order.
+            U.loadFence();
+            if (rn == r) {
+                if (r.queue == ENQUEUED) {
+                    // still enqueued -> we reached end of chain
+                    r = null;
+                } else {
+                    // already dequeued: r.queue == NULL; ->
+                    // restart from head when overtaken by queue poller(s)
+                    r = head;
+                }
+            } else {
+                // next in chain
+                r = rn;
+            }
+        }
+    }
+
+    /* we need a fence */
+    private static final Unsafe U = Unsafe.getUnsafe();
 }