From 4ef977fec3abe84db61e6c4475bf8b49e9872718 Mon Sep 17 00:00:00 2001
From: David Holmes <dholmes@openjdk.org>
Date: Wed, 22 May 2013 20:21:13 -0400
Subject: [PATCH] 8014814: (str) StringBuffer "null" is not appended

Reviewed-by: alanb
---
 .../share/classes/java/lang/StringBuffer.java |  6 ++---
 .../java/lang/StringBuffer/ToStringCache.java | 24 ++++++++++++++++++-
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/jdk/src/share/classes/java/lang/StringBuffer.java b/jdk/src/share/classes/java/lang/StringBuffer.java
index 8ead0721ffd..9bc8f3ba10f 100644
--- a/jdk/src/share/classes/java/lang/StringBuffer.java
+++ b/jdk/src/share/classes/java/lang/StringBuffer.java
@@ -335,10 +335,8 @@ import java.util.Arrays;
      * @since 1.5
      */
     @Override
-    public StringBuffer append(CharSequence s) {
-        // Note, synchronization achieved via invocations of other StringBuffer methods after
-        // narrowing of s to specific type
-        // Ditto for toStringCache clearing
+    public synchronized StringBuffer append(CharSequence s) {
+        toStringCache = null;
         super.append(s);
         return this;
     }
diff --git a/jdk/test/java/lang/StringBuffer/ToStringCache.java b/jdk/test/java/lang/StringBuffer/ToStringCache.java
index 6259e27d0e3..e6c97f0c28a 100644
--- a/jdk/test/java/lang/StringBuffer/ToStringCache.java
+++ b/jdk/test/java/lang/StringBuffer/ToStringCache.java
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 8013395
+ * @bug 8013395 8014814
  * @summary Test StringBuffer.toString caching
  */
 
@@ -199,6 +199,28 @@ public class ToStringCache {
         b = sb.toString();
         checkUnequal(a, b);
 
+        // Extra checks that append(null) works correctly
+
+        sb.append((String)null);
+        b = sb.toString();
+        checkUnequal(a, b);
+        a = b;
+
+        sb.append((StringBuffer)null);
+        b = sb.toString();
+        checkUnequal(a, b);
+        a = b;
+
+        sb.append((StringBuilder)null);
+        b = sb.toString();
+        checkUnequal(a, b);
+        a = b;
+
+        sb.append((CharSequence)null);
+        b = sb.toString();
+        checkUnequal(a, b);
+        a = b;
+
         // non-mutating methods
 
         // Reset to known value