--- jsr166/src/main/java/util/TreeMap.java	2006/05/10 02:31:44	1.38
+++ jsr166/src/main/java/util/TreeMap.java	2007/01/30 03:54:29	1.42
@@ -1,7 +1,7 @@
 /*
  * %W% %E%
  *
- * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
+ * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
  * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
  */
 
@@ -1209,6 +1209,12 @@ public class TreeMap<K,V>
     // SubMaps
 
     /**
+     * Dummy value serving as unmatchable fence key for unbounded
+     * SubMapIterators
+     */
+    private static final Object UNBOUNDED = new Object();
+
+    /**
      * @serial include
      */
     static abstract class NavigableSubMap<K,V> extends AbstractMap<K,V>
@@ -1547,7 +1553,7 @@ public class TreeMap<K,V>
         abstract class SubMapIterator<T> implements Iterator<T> {
             TreeMap.Entry<K,V> lastReturned;
             TreeMap.Entry<K,V> next;
-            final K fenceKey;
+            final Object fenceKey;
             int expectedModCount;
 
             SubMapIterator(TreeMap.Entry<K,V> first,
@@ -1555,7 +1561,7 @@ public class TreeMap<K,V>
                 expectedModCount = m.modCount;
                 lastReturned = null;
                 next = first;
-                fenceKey = fence == null ? null : fence.key;
+                fenceKey = fence == null ? UNBOUNDED : fence.key;
             }
 
             public final boolean hasNext() {
@@ -1689,7 +1695,7 @@ public class TreeMap<K,V>
         }
 
         public NavigableMap<K,V> headMap(K toKey, boolean inclusive) {
-            if (!inClosedRange(toKey))
+            if (!inRange(toKey, inclusive))
                 throw new IllegalArgumentException("toKey out of range");
             return new AscendingSubMap(m,
                                        fromStart, lo,    loInclusive,
@@ -2353,7 +2359,7 @@ public class TreeMap<K,V>
 
         if (hi < lo) return null;
 
-        int mid = (lo + hi) / 2;
+        int mid = (lo + hi) >>> 1;
 
         Entry<K,V> left  = null;
         if (lo < mid)