Update README.md

Author: lor6

core-java-collections/README.md

@@ -30,5 +30,4 @@
 - [Join and Split Arrays and Collections in Java](http://www.baeldung.com/java-join-and-split)
 - [A Guide to EnumMap](https://www.baeldung.com/java-enum-map)
 - [A Guide to Iterator in Java](http://www.baeldung.com/java-iterator)
-- [Intersection of Two Lists in Java](https://www.baeldung.com/java-lists-intersection)
 - [Differences Between HashMap and Hashtable](https://www.baeldung.com/hashmap-hashtable-differences)