Java Programming - Objects and Collections - Discussion

Sorry, but this is a trap question related not to Java/programming knowledge, but definitions knowledge, like "ordered" != "sorted", but most of developers use "order" and "sort" as synonyms, so you confuse people. To be more consistent you should to fix A choice "The elements in the collection are ordered by insertion order".

In same time, D also looks correct! Because every element is accessed by unique key, which is an integer index of element!

The answer is D. ArrayList has a unique key access, and a key is index of array.

If test maker wants to get A for this question they need to clarify or change the test.

In what way are they ordered?
I run:

java.util.ArrayList<Integer> al = new java.util.ArrayList<Integer>();
al.add(4);
al.add(3);
al.add(5);

for (Integer i : al) {
System.out.println(i);
}

And I get
4
3
5
as output. Is that ordered?

I think this question might have a wrong answer. I see no mention of ordering in the docs and as John says above testing it shows it not to be ordered.

In arrayList The colection are ordered in which order they are inserted.

Yes whatever david is exactly right.

Arraylist elements will not be in an order.

So, answer is wrong.

Yes, as @Rahul said the insertion order is preserved. So answer is correct.

ArrayList are meant for random access and they are not in ordered form.

ArrayList are not automatically sorted (unlike TreeSet).

ArrayList are ordered, it keep the same insertion order (unlike HashSet).

Saying that an ArrayList is ordered is wrong, or at least deceiving. The *insertion order* is preserved if you append an object by calling add (E) , but that's quite different, and the definition of "ordered", used in the question, usually refers to the element values (natural ordering).