PriorityQueue offer() Method in Java

The java.util.PriorityQueue.offer() method is used to insert a particular element into the Priority Queue. It acts similar to the add() method of Priority Queue.

Syntax:

Priority_Queue.offer(Object element)

Parameters: The parameter element is of the type PriorityQueue and refers to the element to be inserted into the Queue.

Return Value: The method returns True if the value is successfully inserted into the queue.

Exceptions: The method can throw two types of exceptions:

• NullPointerException: If the element to be inserted is NULL.
• ClassCastException: If an element to be inserted is of a different type that cannot be compared to the existing elements of the Queue.

Below programs illustrate the java.util.PriorityQueue.offer() method
Program 1:

// Java code to illustrate offer()
import java.util.*;

public class PriorityQueueDemo {
    public static void main(String args[])
    {
        // Creating an empty PriorityQueue
        PriorityQueue<String> queue = new PriorityQueue<String>();

        // Use add() method to add elements into the Queue
        queue.add("Welcome");
        queue.add("To");
        queue.add("Geeks");
        queue.add("4");
        queue.add("Geeks");

        // Displaying the PriorityQueue
        System.out.println("Initial PriorityQueue: " + queue);

        // Inserting using offer()
        queue.offer("The");
        queue.offer("Priority");
        queue.offer("Class");

        // Displaying th final Queue
        System.out.println("Priority queue after Insertion: " + queue);
    }
}

Output:

Initial PriorityQueue: [4, Geeks, To, Welcome, Geeks]
Priority queue after Insertion: [4, Class, Priority, Geeks, Geeks, To, The, Welcome]

Program 2:

// Java code to illustrate offer()
import java.util.*;

public class PriorityQueueDemo {
    public static void main(String args[])
    {
        // Creating an empty PriorityQueue
        PriorityQueue<Integer> queue = new PriorityQueue<Integer>();

        // Use add() method to add elements into the Queue
        queue.add(10);
        queue.add(15);
        queue.add(30);
        queue.add(20);
        queue.add(5);

        // Displaying the PriorityQueue
        System.out.println("Initial PriorityQueue: " + queue);

        // Inserting using offer()
        queue.offer(100);
        queue.offer(120);
        queue.offer(150);

        // Displaying th final Queue
        System.out.println("Priority queue after Insertion: " + queue);
    }
}

Output:

Initial PriorityQueue: [5, 10, 30, 20, 15]
Priority queue after Insertion: [5, 10, 30, 20, 15, 100, 120, 150]