--- a/jdk/src/share/classes/java/util/concurrent/Callable.java	Wed Dec 04 09:32:26 2013 -0800
+++ b/jdk/src/share/classes/java/util/concurrent/Callable.java	Wed Dec 04 18:02:33 2013 +0000
@@ -54,6 +54,7 @@
  * @author Doug Lea
  * @param <V> the result type of method {@code call}
  */
+@FunctionalInterface
 public interface Callable<V> {
     /**
      * Computes a result, or throws an exception if unable to do so.