src/java.base/share/classes/java/lang/StringBuffer.java

rev 16193 : imported patch 8170348-StringBuilders-method-to-append-multiple-copies

@@ -425,10 +425,17 @@
         toStringCache = null;
         super.append(d);
         return this;
     }
 
+    @Override
+    public synchronized StringBuffer appendN(char c, int n) {
+        toStringCache = null;
+        super.appendN(c, n);
+        return this;
+    }
+
     /**
      * @throws StringIndexOutOfBoundsException {@inheritDoc}
      * @since      1.2
      */
     @Override