Data Structure and Algorithm 1B

Which of the following is part of the Java Collections Framework?

• String

• Array

• ArrayList

• BufferedReader

What does the List interface in Java guarantee?

• No duplicates and unordered elements

• Unique elements only

• Ordered collection with duplicates allowed

• Sorted collection by default

What is the default initial capacity of an ArrayList in Java?

• 5

• 8

• 10

• 0

Which method is used to sort a List in Java using natural ordering?

• Collections.sort(list)

• list.sort()

• list.sortByNaturalOrder()

• Arrays.sortList()

Which of the following is NOT a valid implementation of the Set interface?

• TreeSet

• HashSet

• LinkedHashSet

• ArrayList

What is the time complexity of add() operation in HashSet (on average)?

• O(n)

• O(1)

• O(log n)

• O(n log n)

Which class allows duplicate elements and maintains insertion order?

• HashSet

• TreeSet

• ArrayList

• HashMap

How does HashSet handle duplicate entries?

• Throws exception

• Replaces existing element

• Ignores duplicate entries

• Adds duplicate at the end

Which method is used to remove all elements from an ArrayList?

• deleteAll()

• removeAll()

• clear()

• reset()

What happens if you try to add a duplicate key to a HashMap?

• It throws an exception

• It ignores the new value

• It replaces the old value

• It stores both values