A Priority Queue is a special type of queue where each element has a priority. Elements with higher priority are served before elements with lower priority. In Java, we can use the built-in PriorityQueue class. By default, it implements a Min-Heap (smallest element is processed first). Java Example

import java.util.PriorityQueue;

public class PriorityQueueDemo {
    public static void main(String[] args) {
        // Min Heap (Default behavior)
        PriorityQueue minHeap = new PriorityQueue();
       
        minHeap.add(30);
        minHeap.add(10);
        minHeap.add(20);

        System.out.println("Processing Min Heap:");
        while (!minHeap.isEmpty()) {
            // poll() removes the head of the queue (smallest element)
            System.out.println(minHeap.poll());
        }
        // Output: 10, 20, 30

        // Max Heap (Custom Comparator)
        PriorityQueue maxHeap = new PriorityQueue((a, b) -> b - a);
       
        maxHeap.add(30);
        maxHeap.add(10);
        maxHeap.add(20);

        System.out.println("\nProcessing Max Heap:");
        while (!maxHeap.isEmpty()) {
            System.out.println(maxHeap.poll());
        }
        // Output: 30, 20, 10
    }
}