Java Queue Methods Quiz: Test Your Knowledge of offer(), poll(), peek(), isEmpty()

📚 Quick Study Guide

• ➕ offer(): Adds an element to the rear of the queue. Returns `true` if the element was added, `false` otherwise (e.g., in a bounded queue).
• 🗑️ poll(): Retrieves and removes the head of the queue. Returns `null` if the queue is empty.
• peek() peek(): Retrieves, but does not remove, the head of the queue. Returns `null` if the queue is empty.
• 🚦 isEmpty(): Checks if the queue is empty. Returns `true` if the queue contains no elements, `false` otherwise.
• ⏳ Queues follow the FIFO (First-In-First-Out) principle. The first element added is the first one to be removed.
• ⚖️ Common implementations include `LinkedList` and `PriorityQueue`.

🧪 Practice Quiz

1. Which method adds an element to the end of a queue in Java?
   1. add()
   2. offer()
   3. push()
   4. insert()
2. What does the `poll()` method do if the queue is empty?
   1. Throws an exception
   2. Returns 0
   3. Returns null
   4. Returns -1
3. Which method retrieves the head of the queue without removing it?
   1. get()
   2. peek()
   3. poll()
   4. remove()
4. What is the return type of the `isEmpty()` method?
   1. int
   2. void
   3. String
   4. boolean
5. Which of the following is NOT a standard method of the Queue interface in Java?
   1. offer()
   2. poll()
   3. peek()
   4. get()
6. What happens when you call `peek()` on an empty queue?
   1. It throws an exception.
   2. It returns a default value.
   3. It returns null.
   4. It returns an empty string.
7. Which data structure principle does a Queue follow?
   1. LIFO (Last-In-First-Out)
   2. FIFO (First-In-First-Out)
   3. Random Access
   4. No specific order