--- old/src/share/classes/java/util/function/Function.java	2012-12-20 16:32:18.200520652 -0800
+++ new/src/share/classes/java/util/function/Function.java	2012-12-20 16:32:17.976520642 -0800
@@ -24,6 +24,8 @@
  */
 package java.util.function;
 
+import java.util.Objects;
+
 /**
  * Apply a function to the input object yielding an appropriate result object. A
  * function may variously provide a mapping between types, object instances or
@@ -44,4 +46,20 @@
      * @return the function result
      */
     public R apply(T t);
+
+    /**
+     * Combine with another function returning a function which performs both
+     * functions.
+     *
+     * @param <V> Type of output objects from the combined function. May be the
+     * same type as {@code <U>}.
+     * @param after An additional function to be applied to the result of this
+     * function.
+     * @return A function which performs both the original function followed by
+     * a second function.
+     */
+    public default <V > Function<T, V> compose(Function<? super R, ? extends V> after) {
+        Objects.requireNonNull(after);
+        return (T t) -> after.apply(apply(t));
+    }
 }