Question

What is the difference between LinkedHashMap and PriorityQueue in Java?

Option 1: LinkedHashMap is a data structure that maintains the order of elements based on insertion, while PriorityQueue is a data structure that orders elements based on their priority.
Option 2: LinkedHashMap is a data structure that orders elements based on their priority, while PriorityQueue maintains the order of elements based on insertion.
Option 3: Both LinkedHashMap and PriorityQueue maintain the order of elements based on insertion.
Option 4: Both LinkedHashMap and PriorityQueue order elements based on their priority.

Answer 1

Option 1 is correct; LinkedHashMap maintains insertion order while PriorityQueue sorts elements based on priority. LinkedHashMap uses a linked list internally to maintain order, whereas PriorityQueue uses a priority heap to determine the natural or defined order of elements for retrieval.

Step-by-step explanation:

The correct answer is Option 1: LinkedHashMap is a data structure that maintains the order of elements based on insertion, while PriorityQueue is a data structure that orders elements based on their priority.

A LinkedHashMap in Java extends HashMap and thus inherits its key-value pair structure, but also maintains a doubly-linked list across all entries. This linked list defines the iteration ordering, which is normally the order in which keys were inserted into the map (insertion-order). However, it can also be configured to order in the sequence keys were last accessed, from least-recently accessed to most-recently (access-order).

On the other hand, a PriorityQueue is a queue data structure that organizes its elements according to a priority heap. When retrieving from the queue, elements are accessed according to their natural ordering, or according to a Comparator provided at queue construction time, not the order in which they were inserted.