Java Collections Quiz

What will be the output? List list = new ArrayList<>(); list.add("Java"); list.add("Python"); list.remove("Java"); System.out.println(list);

• [Java]

• [Python]

• [Java, Python]

• []

What is the output? Set set = new TreeSet<>(); set.add(3); set.add(1); set.add(2); System.out.println(set);

• [3, 2, 1]

• [1, 2, 3]

• [1, 3, 2]

• [2, 1, 3]

What will be printed? List list = Arrays.asList(1, 2, 3); list.set(1, 5); System.out.println(list);

• [1, 2, 3]

• [1, 5, 3]

• [5, 1, 3]

• Compilation error

What will be the result? Queue q = new PriorityQueue<>(); q.add(10); q.add(5); q.add(1); System.out.println(q.peek());

• 10

• 5

• 1

• 0

Output? Deque dq = new LinkedList<>(); dq.addFirst("A"); dq.addLast("B"); System.out.println(dq);

• [B, A]

• [A, B]

• [A]

• [B]

What does this code output? Stack stack = new Stack<>(); stack.push("X"); stack.push("Y"); stack.pop(); System.out.println(stack.peek());

• X

• Y

• null

• Compilation error

What is the result? List list = new LinkedList<>(); list.add("A"); list.add("B"); list.add(1, "C"); System.out.println(list);

• [A, B, C]

• [A, C, B]

• [C, A, B]

• Compilation error

What will be printed? Set set = new HashSet<>(); set.add("One"); set.add("One"); System.out.println(set.size());

• 2

• 1

• 0

• Compilation error

What does the following code output? Map map = new HashMap<>(); map.put("A", 1); map.put("A", 2); System.out.println(map.get("A"));

• 1

• 2

• null

• Compilation error

Output? List list = new ArrayList<>(); System.out.println(list.isEmpty());

• true

• false

• Compilation error

• null