--- old/src/java.base/share/classes/java/util/HashMap.java	2015-01-14 16:29:19.393187548 +0100
+++ new/src/java.base/share/classes/java/util/HashMap.java	2015-01-14 16:29:19.275189702 +0100
@@ -339,10 +339,14 @@
     }
 
     /**
-     * Returns x's Class if it is of the form "class C implements
-     * Comparable<C>", else null.
-     */
-    static Class<?> comparableClassFor(Object x) {
+     * Returns 'cached' if != null, else
+     * returns x's Class if it is of the form "class C implements
+     * Comparable<C>", else void.class.
+     */
+    static Class<?> comparableClassFor(Class<?> cached, Object x) {
+        if (cached != null) {
+            return cached;
+        }
         if (x instanceof Comparable) {
             Class<?> c; Type[] ts, as; ParameterizedType p;
             if ((c = x.getClass()) == String.class) // bypass checks
@@ -358,7 +362,7 @@
                 }
             }
         }
-        return null;
+        return void.class;
     }
 
     /**
@@ -1854,8 +1858,7 @@
                     p = pr;
                 else if (pr == null)
                     p = pl;
-                else if ((kc != null ||
-                          (kc = comparableClassFor(k)) != null) &&
+                else if ((kc = comparableClassFor(kc, k)) != void.class &&
                          (dir = compareComparables(kc, k, pk)) != 0)
                     p = (dir < 0) ? pl : pr;
                 else if ((q = pr.find(h, k, kc)) != null)
@@ -1915,8 +1918,7 @@
                             dir = -1;
                         else if (ph < h)
                             dir = 1;
-                        else if ((kc == null &&
-                                  (kc = comparableClassFor(k)) == null) ||
+                        else if ((kc = comparableClassFor(kc, k)) == void.class ||
                                  (dir = compareComparables(kc, k, pk)) == 0)
                             dir = tieBreakOrder(k, pk);
 
@@ -1969,8 +1971,7 @@
                     dir = 1;
                 else if ((pk = p.key) == k || (k != null && k.equals(pk)))
                     return p;
-                else if ((kc == null &&
-                          (kc = comparableClassFor(k)) == null) ||
+                else if ((kc = comparableClassFor(kc, k)) == void.class ||
                          (dir = compareComparables(kc, k, pk)) == 0) {
                     if (!searched) {
                         TreeNode<K,V> q, ch;