How to find a minimum set of n intersection

public static void main(String[] args) {
    List<String> sameDpCodes = new ArrayList<>();
    List<List<String>> dpCodesList = new ArrayList<>();
    List <String> dpcodes = new ArrayList<>();
    dpcodes.add("aaa");
    dpcodes.add("bbb");
    dpcodes.add("ccc");
    List <String> dpcodes1 = new ArrayList<>();
    dpcodes1.add("ccc");
    dpcodes1.add("eee");
    dpcodes1.add("fff");
    List <String> dpcodes2 = new ArrayList<>();
    dpcodes2.add("ddd");
    dpcodes2.add("ggg");
    dpcodes2.add("hhh");
    dpCodesList.add(dpcodes);
    dpCodesList.add(dpcodes2);
    dpCodesList.add(dpcodes1);
    for (List <String> dpCodes: dpCodesList) { 


        IF (dpCodes.isEmpty ()) { 
            Continue; 
        } 

        IF (sameDpCodes.isEmpty ()) { 
            sameDpCodes.addAll (dpCodes); 
            Continue; 
        } 

        sameDpCodes.retainAll (dpCodes); 

        IF (sameDpCodes.isEmpty ()) { 
            System.out.println ( "empty"); 
        } 
    } 
    System.out.println (sameDpCodes); 
} 
being a little bug, but you do not affect my business, because I was empty of output when direct return out, it does not affect the future and so have time to improve it