diff -r 836adbf7a2cd -r 3317bb8137f4 jdk/src/java.base/share/classes/java/util/RegularEnumSet.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.base/share/classes/java/util/RegularEnumSet.java	Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,304 @@
+/*
+ * Copyright (c) 2003, 2012, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.
+ */
+
+package java.util;
+
+/**
+ * Private implementation class for EnumSet, for "regular sized" enum types
+ * (i.e., those with 64 or fewer enum constants).
+ *
+ * @author Josh Bloch
+ * @since 1.5
+ * @serial exclude
+ */
+class RegularEnumSet<E extends Enum<E>> extends EnumSet<E> {
+    private static final long serialVersionUID = 3411599620347842686L;
+    /**
+     * Bit vector representation of this set.  The 2^k bit indicates the
+     * presence of universe[k] in this set.
+     */
+    private long elements = 0L;
+
+    RegularEnumSet(Class<E>elementType, Enum<?>[] universe) {
+        super(elementType, universe);
+    }
+
+    void addRange(E from, E to) {
+        elements = (-1L >>>  (from.ordinal() - to.ordinal() - 1)) << from.ordinal();
+    }
+
+    void addAll() {
+        if (universe.length != 0)
+            elements = -1L >>> -universe.length;
+    }
+
+    void complement() {
+        if (universe.length != 0) {
+            elements = ~elements;
+            elements &= -1L >>> -universe.length;  // Mask unused bits
+        }
+    }
+
+    /**
+     * Returns an iterator over the elements contained in this set.  The
+     * iterator traverses the elements in their <i>natural order</i> (which is
+     * the order in which the enum constants are declared). The returned
+     * Iterator is a "snapshot" iterator that will never throw {@link
+     * ConcurrentModificationException}; the elements are traversed as they
+     * existed when this call was invoked.
+     *
+     * @return an iterator over the elements contained in this set
+     */
+    public Iterator<E> iterator() {
+        return new EnumSetIterator<>();
+    }
+
+    private class EnumSetIterator<E extends Enum<E>> implements Iterator<E> {
+        /**
+         * A bit vector representing the elements in the set not yet
+         * returned by this iterator.
+         */
+        long unseen;
+
+        /**
+         * The bit representing the last element returned by this iterator
+         * but not removed, or zero if no such element exists.
+         */
+        long lastReturned = 0;
+
+        EnumSetIterator() {
+            unseen = elements;
+        }
+
+        public boolean hasNext() {
+            return unseen != 0;
+        }
+
+        @SuppressWarnings("unchecked")
+        public E next() {
+            if (unseen == 0)
+                throw new NoSuchElementException();
+            lastReturned = unseen & -unseen;
+            unseen -= lastReturned;
+            return (E) universe[Long.numberOfTrailingZeros(lastReturned)];
+        }
+
+        public void remove() {
+            if (lastReturned == 0)
+                throw new IllegalStateException();
+            elements &= ~lastReturned;
+            lastReturned = 0;
+        }
+    }
+
+    /**
+     * Returns the number of elements in this set.
+     *
+     * @return the number of elements in this set
+     */
+    public int size() {
+        return Long.bitCount(elements);
+    }
+
+    /**
+     * Returns <tt>true</tt> if this set contains no elements.
+     *
+     * @return <tt>true</tt> if this set contains no elements
+     */
+    public boolean isEmpty() {
+        return elements == 0;
+    }
+
+    /**
+     * Returns <tt>true</tt> if this set contains the specified element.
+     *
+     * @param e element to be checked for containment in this collection
+     * @return <tt>true</tt> if this set contains the specified element
+     */
+    public boolean contains(Object e) {
+        if (e == null)
+            return false;
+        Class<?> eClass = e.getClass();
+        if (eClass != elementType && eClass.getSuperclass() != elementType)
+            return false;
+
+        return (elements & (1L << ((Enum<?>)e).ordinal())) != 0;
+    }
+
+    // Modification Operations
+
+    /**
+     * Adds the specified element to this set if it is not already present.
+     *
+     * @param e element to be added to this set
+     * @return <tt>true</tt> if the set changed as a result of the call
+     *
+     * @throws NullPointerException if <tt>e</tt> is null
+     */
+    public boolean add(E e) {
+        typeCheck(e);
+
+        long oldElements = elements;
+        elements |= (1L << ((Enum<?>)e).ordinal());
+        return elements != oldElements;
+    }
+
+    /**
+     * Removes the specified element from this set if it is present.
+     *
+     * @param e element to be removed from this set, if present
+     * @return <tt>true</tt> if the set contained the specified element
+     */
+    public boolean remove(Object e) {
+        if (e == null)
+            return false;
+        Class<?> eClass = e.getClass();
+        if (eClass != elementType && eClass.getSuperclass() != elementType)
+            return false;
+
+        long oldElements = elements;
+        elements &= ~(1L << ((Enum<?>)e).ordinal());
+        return elements != oldElements;
+    }
+
+    // Bulk Operations
+
+    /**
+     * Returns <tt>true</tt> if this set contains all of the elements
+     * in the specified collection.
+     *
+     * @param c collection to be checked for containment in this set
+     * @return <tt>true</tt> if this set contains all of the elements
+     *        in the specified collection
+     * @throws NullPointerException if the specified collection is null
+     */
+    public boolean containsAll(Collection<?> c) {
+        if (!(c instanceof RegularEnumSet))
+            return super.containsAll(c);
+
+        RegularEnumSet<?> es = (RegularEnumSet<?>)c;
+        if (es.elementType != elementType)
+            return es.isEmpty();
+
+        return (es.elements & ~elements) == 0;
+    }
+
+    /**
+     * Adds all of the elements in the specified collection to this set.
+     *
+     * @param c collection whose elements are to be added to this set
+     * @return <tt>true</tt> if this set changed as a result of the call
+     * @throws NullPointerException if the specified collection or any
+     *     of its elements are null
+     */
+    public boolean addAll(Collection<? extends E> c) {
+        if (!(c instanceof RegularEnumSet))
+            return super.addAll(c);
+
+        RegularEnumSet<?> es = (RegularEnumSet<?>)c;
+        if (es.elementType != elementType) {
+            if (es.isEmpty())
+                return false;
+            else
+                throw new ClassCastException(
+                    es.elementType + " != " + elementType);
+        }
+
+        long oldElements = elements;
+        elements |= es.elements;
+        return elements != oldElements;
+    }
+
+    /**
+     * Removes from this set all of its elements that are contained in
+     * the specified collection.
+     *
+     * @param c elements to be removed from this set
+     * @return <tt>true</tt> if this set changed as a result of the call
+     * @throws NullPointerException if the specified collection is null
+     */
+    public boolean removeAll(Collection<?> c) {
+        if (!(c instanceof RegularEnumSet))
+            return super.removeAll(c);
+
+        RegularEnumSet<?> es = (RegularEnumSet<?>)c;
+        if (es.elementType != elementType)
+            return false;
+
+        long oldElements = elements;
+        elements &= ~es.elements;
+        return elements != oldElements;
+    }
+
+    /**
+     * Retains only the elements in this set that are contained in the
+     * specified collection.
+     *
+     * @param c elements to be retained in this set
+     * @return <tt>true</tt> if this set changed as a result of the call
+     * @throws NullPointerException if the specified collection is null
+     */
+    public boolean retainAll(Collection<?> c) {
+        if (!(c instanceof RegularEnumSet))
+            return super.retainAll(c);
+
+        RegularEnumSet<?> es = (RegularEnumSet<?>)c;
+        if (es.elementType != elementType) {
+            boolean changed = (elements != 0);
+            elements = 0;
+            return changed;
+        }
+
+        long oldElements = elements;
+        elements &= es.elements;
+        return elements != oldElements;
+    }
+
+    /**
+     * Removes all of the elements from this set.
+     */
+    public void clear() {
+        elements = 0;
+    }
+
+    /**
+     * Compares the specified object with this set for equality.  Returns
+     * <tt>true</tt> if the given object is also a set, the two sets have
+     * the same size, and every member of the given set is contained in
+     * this set.
+     *
+     * @param o object to be compared for equality with this set
+     * @return <tt>true</tt> if the specified object is equal to this set
+     */
+    public boolean equals(Object o) {
+        if (!(o instanceof RegularEnumSet))
+            return super.equals(o);
+
+        RegularEnumSet<?> es = (RegularEnumSet<?>)o;
+        if (es.elementType != elementType)
+            return elements == 0 && es.elements == 0;
+        return es.elements == elements;
+    }
+}