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diff --git a/guava/src/com/google/common/collect/NaturalOrdering.java b/guava/src/com/google/common/collect/NaturalOrdering.java
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+++ b/guava/src/com/google/common/collect/NaturalOrdering.java
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+/*
+ * Copyright (C) 2007 The Guava Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.common.collect;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.annotations.GwtCompatible;
+
+import java.io.Serializable;
+import java.util.Collections;
+import java.util.List;
+
+/** An ordering that uses the natural order of the values. */
+@GwtCompatible(serializable = true)
+@SuppressWarnings("unchecked") // TODO(kevinb): the right way to explain this??
+final class NaturalOrdering
+    extends Ordering<Comparable> implements Serializable {
+  static final NaturalOrdering INSTANCE = new NaturalOrdering();
+
+  @Override public int compare(Comparable left, Comparable right) {
+    checkNotNull(left); // for GWT
+    checkNotNull(right);
+    if (left == right) {
+      return 0;
+    }
+
+    return left.compareTo(right);
+  }
+
+  @Override public <S extends Comparable> Ordering<S> reverse() {
+    return (Ordering<S>) ReverseNaturalOrdering.INSTANCE;
+  }
+
+  // Override to remove a level of indirection from inner loop
+  @Override public int binarySearch(
+      List<? extends Comparable> sortedList, Comparable key) {
+    return Collections.binarySearch((List) sortedList, key);
+  }
+
+  // Override to remove a level of indirection from inner loop
+  @Override public <E extends Comparable> List<E> sortedCopy(
+      Iterable<E> iterable) {
+    List<E> list = Lists.newArrayList(iterable);
+    Collections.sort(list);
+    return list;
+  }
+
+  // preserving singleton-ness gives equals()/hashCode() for free
+  private Object readResolve() {
+    return INSTANCE;
+  }
+
+  @Override public String toString() {
+    return "Ordering.natural()";
+  }
+
+  private NaturalOrdering() {}
+
+  private static final long serialVersionUID = 0;
+}