1. What is a LinkedList in Java?
Answer:
Explanation:
A LinkedList in Java is a linear data structure where each element (node) is linked to its next and previous elements.
2. How does a LinkedList differ from an ArrayList in Java?
Answer:
Explanation:
Unlike ArrayLists, LinkedLists in Java are designed for efficient insertion and removal operations.
3. Which interface does LinkedList implement in Java?
Answer:
Explanation:
LinkedList implements the List interface, providing ordered collection behavior.
4. Can a Java LinkedList contain duplicate elements?
Answer:
Explanation:
LinkedList can contain duplicate elements, as it allows multiple null and duplicate values.
5. How do you add an element at the beginning of a LinkedList?
Answer:
Explanation:
The addFirst() method is used to insert an element at the beginning of a LinkedList.
6. What method is used to remove the last element of a LinkedList?
Answer:
Explanation:
The removeLast() method removes and returns the last element of the LinkedList.
7. Which of these methods retrieves, but does not remove, the head of a LinkedList?
Answer:
Explanation:
getFirst(), peek(), and element() methods retrieve but do not remove the head of the LinkedList.
8. What is the complexity of removing an element from the middle of a LinkedList?
Answer:
Explanation:
Removing an element from the middle of a LinkedList has a time complexity of O(n) because it may require traversing the list.
9. How do you reverse a LinkedList in Java?
Answer:
Explanation:
Collections.reverse() can be used to reverse a LinkedList in Java.
10. What happens when you add elements to a LinkedList using add() method?
Answer:
Explanation:
The add() method in LinkedList adds elements to the end of the list.
11. Can you use a for-each loop to iterate over a LinkedList?
Answer:
Explanation:
LinkedLists in Java can be iterated over using a for-each loop.
12. What is the method to retrieve and remove the first element of a LinkedList?
Answer:
Explanation:
The removeFirst() and pop() methods both retrieve and remove the first element of the LinkedList.
13. What happens if you try to access an index that is out of bounds in a LinkedList?
Answer:
Explanation:
Accessing an out-of-bounds index in a LinkedList results in an IndexOutOfBoundsException.
14. Is LinkedList synchronized in Java?
Answer:
Explanation:
LinkedList is not synchronized by default. If multiple threads access it concurrently, external synchronization is required.
15. How can you convert a LinkedList to an array in Java?
Answer:
Explanation:
The toArray() method can be used to convert a LinkedList into an array, making it an effective way to transition between these two data structures.