--- /dev/null	2012-10-10 14:09:44.988864763 -0400
+++ new/./test/java/lang/StringBuilder/AppendStringBuffer.java	2012-10-10 16:16:38.110855274 -0400
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+ * @bug 6206780
+ * @summary Test StringBuilder.append(StringBuffer);
+ */
+
+import java.util.Random;
+
+public class AppendStringBuffer {
+    private static Random generator = new Random();
+
+    public static void main(String[] args) throws Exception {
+        for (int i=0; i<1000; i++) {
+            StringBuffer sb1 = generateTestBuffer(10, 100);
+            StringBuffer sb2 = generateTestBuffer(10, 100);
+            StringBuffer sb3 = generateTestBuffer(10, 100);
+            String s1 = sb1.toString();
+            String s2 = sb2.toString();
+            String s3 = sb3.toString();
+
+            String concatResult = new String(s1+s2+s3);
+
+            StringBuilder test = new StringBuilder();
+            test.append(sb1);
+            test.append(sb2);
+            test.append(sb3);
+
+            if (!test.toString().equals(concatResult))
+                throw new RuntimeException("StringBuffer.append failure");
+        }
+    }
+
+    private static int getRandomIndex(int constraint1, int constraint2) {
+        int range = constraint2 - constraint1;
+        int x = generator.nextInt(range);
+        return constraint1 + x;
+    }
+
+    private static StringBuffer generateTestBuffer(int min, int max) {
+        StringBuffer aNewStringBuffer = new StringBuffer(120);
+        int aNewLength = getRandomIndex(min, max);
+        for(int y=0; y<aNewLength; y++) {
+            int achar = generator.nextInt(30)+30;
+            char test = (char)(achar);
+            aNewStringBuffer.append(test);
+        }
+        return aNewStringBuffer;
+    }
+}