diff -r 31d23e077ab3 -r 032254f2467b jdk/src/share/classes/java/util/function/UnaryOperator.java
--- a/jdk/src/share/classes/java/util/function/UnaryOperator.java	Wed May 15 10:25:59 2013 +0200
+++ b/jdk/src/share/classes/java/util/function/UnaryOperator.java	Fri May 17 10:36:04 2013 -0700
@@ -36,4 +36,13 @@
  */
 @FunctionalInterface
 public interface UnaryOperator<T> extends Function<T, T> {
+
+    /**
+     * Returns a unary operator that provides its input value as the result.
+     *
+     * @return a unary operator that provides its input value as the result
+     */
+    static <T> UnaryOperator<T> identity() {
+        return t -> t;
+    }
 }