Java peek method, Example PriorityQueue peek() method.

Java peek method, Example PriorityQueue peek() method.

In this example, you will see the use of peek() method of java PriorityQueue class. It retrieves the head of this queue, but does not remove it. If queue is empty than it returns null.

Code:

SizeOfPriorityQueue.java

import java.util.Iterator;
import java.util.PriorityQueue;

public class PriorityQueuePeekMethod {
public static void main(String[] args) {
	PriorityQueue obPriorQueue = new PriorityQueue();
	obPriorQueue.add("B");
	obPriorQueue.add("A");
	obPriorQueue.add("C");
	obPriorQueue.add("D");
	obPriorQueue.add("E");
	System.out
	.println("Before using peek method elements in priority queue : ");
	Iterator oIterator = obPriorQueue.iterator();
	while (oIterator.hasNext()) {
	System.out.print(oIterator.next() + " ");
	}
	System.out.println("\n Head element : ");
	System.out.print(obPriorQueue.peek());
	System.out.println("\nAfter peek method elements in priority queue : ");
	Iterator obIterator = obPriorQueue.iterator();
	while (obIterator.hasNext()) {
	System.out.print(obIterator.next() + " ");
	}
    }
}