--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/ScriptRuntime.java	Wed Jul 05 21:41:01 2017 +0200
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/ScriptRuntime.java	Tue May 10 22:26:51 2016 +0530
@@ -313,18 +313,8 @@
         }
     }
 
-    /**
-     * Returns an iterator over property values used in the {@code for each...in} statement. Aside from built-in JS
-     * objects, it also operates on Java arrays, any {@link Iterable}, as well as on {@link Map} objects, iterating over
-     * map values.
-     * @param obj object to iterate on.
-     * @return iterator over the object's property values.
-     */
-    public static Iterator<?> toValueIterator(final Object obj) {
-        if (obj instanceof ScriptObject) {
-            return ((ScriptObject)obj).valueIterator();
-        }
-
+    // value Iterator for important Java objects - arrays, maps, iterables.
+    private static Iterator<?> iteratorForJavaArrayOrList(final Object obj) {
         if (obj != null && obj.getClass().isArray()) {
             final Object array  = obj;
             final int    length = Array.getLength(obj);
@@ -352,18 +342,38 @@
             };
         }
 
+        if (obj instanceof Iterable) {
+            return ((Iterable<?>)obj).iterator();
+        }
+
+        return null;
+    }
+
+    /**
+     * Returns an iterator over property values used in the {@code for each...in} statement. Aside from built-in JS
+     * objects, it also operates on Java arrays, any {@link Iterable}, as well as on {@link Map} objects, iterating over
+     * map values.
+     * @param obj object to iterate on.
+     * @return iterator over the object's property values.
+     */
+    public static Iterator<?> toValueIterator(final Object obj) {
+        if (obj instanceof ScriptObject) {
+            return ((ScriptObject)obj).valueIterator();
+        }
+
         if (obj instanceof JSObject) {
             return ((JSObject)obj).values().iterator();
         }
 
+        final Iterator<?> itr = iteratorForJavaArrayOrList(obj);
+        if (itr != null) {
+            return itr;
+        }
+
         if (obj instanceof Map) {
             return ((Map<?,?>)obj).values().iterator();
         }
 
-        if (obj instanceof Iterable) {
-            return ((Iterable<?>)obj).iterator();
-        }
-
         final Object wrapped = Global.instance().wrapAsObject(obj);
         if (wrapped instanceof ScriptObject) {
             return ((ScriptObject)wrapped).valueIterator();
@@ -380,6 +390,14 @@
      * @return iterator based on the ECMA 6 Iterator interface.
      */
     public static Iterator<?> toES6Iterator(final Object obj) {
+        // if not a ScriptObject, try convenience iterator for Java objects!
+        if (!(obj instanceof ScriptObject)) {
+            final Iterator<?> itr = iteratorForJavaArrayOrList(obj);
+            if (itr != null) {
+                return itr;
+            }
+        }
+
         final Global global = Global.instance();
         final Object iterator = AbstractIterator.getIterator(Global.toObject(obj), global);
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/es6/JDK-8156665.js	Tue May 10 22:26:51 2016 +0530
@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2016, 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.
+ */
+
+/**
+ * JDK-8156665: ES6 for..of should work on Java Iterables and Java arrays
+ *
+ * @test
+ * @run
+ * @option --language=es6
+ */
+
+var ca = new (Java.type("char[]"))(3);
+ca[0] = 'a', ca[1] = 'b', ca[2] = 'c';
+for (i of ca) print(i);
+
+var al = new java.util.ArrayList();
+al.add("hello");
+al.add("world");
+
+for (i of al) print(i);

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/es6/JDK-8156665.js.EXPECTED	Tue May 10 22:26:51 2016 +0530
@@ -0,0 +1,5 @@
+a
+b
+c
+hello
+world