Collections Framework – Multiple Choice Questions (MCQs)

1. 13. Which interface provides methods for accessing elements in a sequential manner?

   • A. List
   • B. Set
   • C. Iterator
   • D. Map

2. 14. How do you iterate over the elements of a `Collection` using an `Iterator`?

   • A. Using a for-each loop
   • B. Using a while loop with `iterator.next()` and `iterator.hasNext()`
   • C. Using a traditional for loop with index
   • D. Using a do-while loop

3. 15. What is the purpose of the `ListIterator` interface?

   • A. To iterate over `Set` elements
   • B. To iterate over `Map` entries
   • C. To iterate over `List` elements in both forward and backward directions
   • D. To iterate over `Queue` elements

4. 16. What are generics in the Java Collections Framework?

   • A. A way to store multiple data types in a collection
   • B. A mechanism to provide type safety for collections
   • C. A way to improve the performance of collections
   • D. A feature for sorting collections

5. 17. How do you declare an `ArrayList` that can only store `String` objects?

   • A. ArrayList strings = new ArrayList();
   • B. ArrayList<String> strings = new ArrayList<String>;
   • C. ArrayList[String] strings = new ArrayList[String];
   • D. List<String> strings = new List<String>();

6. 18. What happens if you try to add an object of a different type to a generic collection?

   • A. A runtime exception is thrown
   • B. The object is automatically cast
   • C. A compile-time error occurs
   • D. The object is ignored

7. 19. Which interface represents a collection that does not allow duplicate elements and provides methods for accessing elements in sorted order?

   • A. Set
   • B. SortedSet
   • C. NavigableSet
   • D. TreeSet

8. 20. Which class implements the `SortedSet` interface?

   • A. HashSet
   • B. LinkedHashSet
   • C. TreeSet
   • D. ArrayList

9. 21. Which interface represents a map that provides methods for accessing entries in sorted order of keys?

   • A. Map
   • B. SortedMap
   • C. NavigableMap
   • D. TreeMap

10. 22. Which class implements the `SortedMap` interface?

    • A. HashMap
    • B. LinkedHashMap
    • C. TreeMap
    • D. ArrayList

11. 23. What is the purpose of the `Comparable` interface?

    • A. To define a natural ordering for objects of a class
    • B. To provide custom comparison logic for sorting
    • C. To check if two objects are equal
    • D. To convert an object to a string

12. 24. What is the purpose of the `Comparator` interface?

    • A. To define a natural ordering for objects of a class
    • B. To provide custom comparison logic for sorting
    • C. To check if two objects are equal
    • D. To convert an object to a string