--- a/jdk/src/share/classes/java/lang/AbstractStringBuilder.java	Tue Mar 26 13:34:54 2013 -0700
+++ b/jdk/src/share/classes/java/lang/AbstractStringBuilder.java	Tue Mar 26 13:36:51 2013 -0700
@@ -236,7 +236,7 @@
         if ((index < 0) || (index >= count)) {
             throw new StringIndexOutOfBoundsException(index);
         }
-        return Character.codePointAt(value, index);
+        return Character.codePointAtImpl(value, index, count);
     }
 
     /**
@@ -265,7 +265,7 @@
         if ((i < 0) || (i >= count)) {
             throw new StringIndexOutOfBoundsException(index);
         }
-        return Character.codePointBefore(value, index);
+        return Character.codePointBeforeImpl(value, index, 0);
     }
 
     /**
@@ -1370,32 +1370,37 @@
      * @return  a reference to this object.
      */
     public AbstractStringBuilder reverse() {
-        boolean hasSurrogate = false;
+        boolean hasSurrogates = false;
         int n = count - 1;
-        for (int j = (n-1) >> 1; j >= 0; --j) {
-            char temp = value[j];
-            char temp2 = value[n - j];
-            if (!hasSurrogate) {
-                hasSurrogate = (temp >= Character.MIN_SURROGATE && temp <= Character.MAX_SURROGATE)
-                    || (temp2 >= Character.MIN_SURROGATE && temp2 <= Character.MAX_SURROGATE);
+        for (int j = (n-1) >> 1; j >= 0; j--) {
+            int k = n - j;
+            char cj = value[j];
+            char ck = value[k];
+            value[j] = ck;
+            value[k] = cj;
+            if (Character.isSurrogate(cj) ||
+                Character.isSurrogate(ck)) {
+                hasSurrogates = true;
             }
-            value[j] = temp2;
-            value[n - j] = temp;
+        }
+        if (hasSurrogates) {
+            reverseAllValidSurrogatePairs();
         }
-        if (hasSurrogate) {
-            // Reverse back all valid surrogate pairs
-            for (int i = 0; i < count - 1; i++) {
-                char c2 = value[i];
-                if (Character.isLowSurrogate(c2)) {
-                    char c1 = value[i + 1];
-                    if (Character.isHighSurrogate(c1)) {
-                        value[i++] = c1;
-                        value[i] = c2;
-                    }
+        return this;
+    }
+
+    /** Outlined helper method for reverse() */
+    private void reverseAllValidSurrogatePairs() {
+        for (int i = 0; i < count - 1; i++) {
+            char c2 = value[i];
+            if (Character.isLowSurrogate(c2)) {
+                char c1 = value[i + 1];
+                if (Character.isHighSurrogate(c1)) {
+                    value[i++] = c1;
+                    value[i] = c2;
                 }
             }
         }
-        return this;
     }
 
     /**