A priority queue is a special type of queue that orders elements based on their priority. Elements with higher priority are dequeued before lower-priority elements. PriorityQueue uses a heap data structure internally to provide efficient O(log n) time for enqueue and dequeue operations.

In this article, we will learn how to convert an ArrayList and an Array into a PriorityQueue in Java.

Syntax of converting an ArrayList into a PriorityQueue:

ArrayList<T> arrayList = new ArrayList<>();
PriorityQueue<T> priorityQueue = new PriorityQueue<>(arrayList);

Program to Convert an ArrayList into a PriorityQueue in Java

Below is the implementation to convert an ArrayList into a PriorityQueue Java.

C++ Java Python 

Explanation of above code:

• An ArrayList of courses created.
• Then it converted to PriorityQueue using constructor.
• For-each loop iterates PriorityQueue.
• Elements printed separated by space.

Syntax of converting an Array into a PriorityQueue:

T[] array = { /* elements of the arary */ };
PriorityQueue<T> priorityQueue = new PriorityQueue<>(Arrays.asList(array));

Program to Convert an Array into a PriorityQueue in Java

Below is the implementation to convert an Array into a PriorityQueue Java

C++ Java Python 

Explanation of above code:

• The array of strings {“C++”, “Java”, “Python”} is converted to a PriorityQueue using Arrays.asList().
• A PriorityQueue orders elements in ascending natural order by default.
• So, when iterating over the PriorityQueue, the elements will be in order of their ASCII values – “C++”, “Java”, “Python”.
• Therefore, the output printed will be: C++ Java Python.