@Override
public boolean equals(Object object)
{
    boolean isEqual= false;

    if (object != null && object instanceof A)
    {
        isEqual = (this.elementA == ((A) object).elementA);
    }

    return isEqual;
}

@Override
public int hashCode() {
    return this.elementA;
}

boolean contains = CollectionUtils.exists(myArrayList, new Predicate<A>() {
    public boolean evaluate(A theA) {
        // Do the comparison
    }
});

ArrayList<String> l1 = new ArrayList<>();
    ArrayList<String> l2 = new ArrayList<>();
    l1.add("asdf");
    l2.add("asdf");
    ArrayList<ArrayList<String>> coll = new ArrayList<>();
    coll.add(l1);
    System.out.println(coll.contains(l2));

Map<Integer, A> map = new HashMap<>();
A a1 = new A(1, 1);
A a2 = new A(1, 2);

map.put(a1.elementA, a1);

// test if key is contained
boolean contains = map.containsKey(a2.elementA);

// overwrite a1 with a2
map.put(a2.elementA, a2);

Ex:
List<String> myList = new ArrayList<String>();

For comparing the object value in arrayList.

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