Java Programming - MCQ Practice Questions

Which interface in Java Collections Framework is used to maintain insertion order while allowing duplicates?

What is the time complexity of get() operation in HashMap in average case?

Which collection class is synchronized and thread-safe by default?

What does the PriorityQueue in Java Collections Framework guarantee?

Consider: List<String> list = new ArrayList<>(); list.add("Java"); list.add("Python"); What will list.get(1) return?

Which method returns true if the map contains the specified value?

Which of the following collections maintains insertion order while allowing fast random access?

What will be the output of the following code? Set<Integer> set = new TreeSet<>(); set.add(5); set.add(2); set.add(8); set.add(2); System.out.println(set.size());

What will happen when you execute: Map<String, String> map = new HashMap<>(); map.put("key", null); System.out.println(map.get("key"));