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Java Quiz Day 37
Question 1
Which of the following classes implement the List interface in Java?
- A
HashMap
- B
HashSet
- C
ArrayList
- D
TreeMap
Question 2
Which class among ArrayList, LinkedList, Vector, and Stack is synchronized (thread-safe)?
- A
ArrayList
- B
LinkedList
- C
Vector
- D
None of the above
Question 3
What is the time complexity of inserting an element at the beginning of an ArrayList?
- A
O(1)
- B
O(n)
- C
O(log n)
- D
O(n log n)
Question 4
Which data structure is best for implementing a LIFO (Last In First Out) operation in Java?
- A
Queue
- B
Stack
- C
LinkedList
- D
PriorityQueue
Question 5
Which of the following allows fast insertions and deletions at both ends?
- A
ArrayList
- B
LinkedList
- C
Vector
- D
Stack
Question 6
What happens if you try to access an invalid index in an ArrayList?
- A
It returns
null - B
It throws
ArrayIndexOutOfBoundsException - C
It throws
NullPointerException - D
It throws
IndexOutOfBoundsException
Question 7
How do you retrieve the top element from a Stack without removing it?
- A
pop() - B
peek() - C
top() - D
get()
Question 8
Which collection should you prefer when frequent insertions and deletions are required in the middle of the list?
- A
ArrayList
- B
Vector
- C
LinkedList
- D
Stack
Question 9
Which collection type does NOT allow random access to its elements?
- A
ArrayList
- B
HashSet
- C
LinkedList
- D
TreeSet
There are 9 questions to complete.