Fix link to FunctionalInterface javadoc

Author: adriaanm

README.md

@@ -4,7 +4,7 @@ A Java 8 compatibility kit for Scala.
 
 ### Functional Interfaces for Scala functions
 
-A set of [Functional Interfaces](http://download.java.net/jdk8/docs/api/java/lang/FunctionalInterface.html)
+A set of [Functional Interfaces](https://docs.oracle.com/javase/8/docs/api/java/lang/FunctionalInterface.html)
 for `scala.FunctionN`. These are designed for convenient construction of Scala functions
 using Java 8 lambda syntax.