Inverse Compare Hashmap ArrayList

InverseCompare.java

public class InverseCompare {
    public static final String ID = "id";
    public static final String ANIMALNAME = "animalName";

    public static void main(String[] args) {
        ArrayList<Map<String, Object>> myList = new ArrayList<>(4); // what we have now.


        Map<String, Object> map0 = new HashMap<>();
        Map<String, Object> map1 = new HashMap<>();


        map0.put(ANIMALNAME, "dog");
        map0.put(ID, (int) (Math.random() * 100 - 10) + 10);

        map1.put(ANIMALNAME, "cat");
        map1.put(ID, (int) (Math.random() * 100 - 10) + 10);


        //add random data, in a random fashion
        myList.add(map1);
        myList.add(map0);


        List<String> a1 = Arrays.asList("dog", "cat", "zebra", "duck", "cow"); // from database.

        List<String> a3 = new ArrayList<>();
        for (String s : a1) {
            Set<String> uniqueValues = new HashSet<>();
            for (Map<String, Object> kk : myList) {
                if (!s.equals(kk.get(ANIMALNAME))) {
                    if (uniqueValues.add(s)) {
                        a3.add(s);
                    }
                }
            }
        }



        // GOAL: FILTER absent from on our hand.
        // formula: absent = database - OnHand


        System.out.println(a3);

    }
}

or alternative (shorter, using Streams:

List<String> a3 = new ArrayList<>();
       for (String s : a1) {
           myList.stream()
                   .filter(kk -> !s.equals(kk.get(ANIMALNAME)))
                   .map(kk -> s)
                   .distinct()
                   .forEach(a3::add);
       }