import java.util.*;
import java.util.Collection;

public class CollectionInterfaceRetainAllMethod {
 public static void main(String[] args){
 Collection collection =  new LinkedList();
 ArrayList arraylist =  new ArrayList();
 collection.add(1);
 collection.add(2);
 collection.add(3);
 collection.add(4);
 
 arraylist.add(1);
 arraylist.add(2);
 System.out.println("Before retainAll :" + collection);
 collection.retainAll(arraylist);
 System.out.println("After retainAll :" + arraylist);
 System.out.println("After retainAll :" + collection);
 }
}