--- old/src/java.base/share/classes/java/lang/Appendable.java	2016-12-09 08:31:41.810372432 +0100
+++ new/src/java.base/share/classes/java/lang/Appendable.java	2016-12-09 08:31:41.671373476 +0100
@@ -118,4 +118,29 @@
      *          If an I/O error occurs
      */
     Appendable append(char c) throws IOException;
+
+    /**
+     * Appends {@code n} copies of the specified character to this
+     * {@code Appendable}.
+     *
+     * @param  c
+     *         The character to append
+     * @param  n
+     *         The number of copies
+     *
+     * @return  A reference to this {@code Appendable}
+     *
+     * @throws  IOException
+     *          If an I/O error occurs
+     * @throws  IllegalArgumentException
+     *          If {@code n} is negative
+     */
+    default Appendable appendN(char c, int n) throws IOException {
+        if (n < 0) {
+            throw new IllegalArgumentException("Negative number of"
+                    + " copies: " + n);
+        }
+        StringBuilder sb = new StringBuilder(n);
+        return append(sb.appendN(c, n));
+    }
 }