--- old/src/share/classes/java/util/TreeMap.java	2011-03-10 15:50:01.000000000 -0800
+++ new/src/share/classes/java/util/TreeMap.java	2011-03-10 15:50:01.000000000 -0800
@@ -528,11 +528,12 @@
     public V put(K key, V value) {
         Entry<K,V> t = root;
         if (t == null) {
-            // TBD:
-            // 5045147: (coll) Adding null to an empty TreeSet should
-            // throw NullPointerException
-            //
-            // compare(key, key); // type check
+            if (key == null) {
+                if (comparator == null) {
+                    throw new NullPointerException();
+                }
+                comparator.compare(key, key); // type check
+            }
             root = new Entry<>(key, value, null);
             size = 1;
             modCount++;