Java ArrayBlockingQueue peek() Method

Last Updated : 17 Mar 2025

The peek() method of Java ArrayBlockingQueue class retrieves the head of this queue, but doesn't remove it. The method returns null if this queue is empty.

Syntax:

Parameters:

Specified By:

The peek() method of ArrayBlockingQueue class is specified by peek() method in interface Queue.

Return Value:

The peek() method returns this queue's head and if this queue is empty,it returns null.

Example 1

import java.util.concurrent.ArrayBlockingQueue;
public class ArrayBlockingQueuePeekExample1 {
    public static void main(String[] args) {
        int capacity =100;
        ArrayBlockingQueue<String> queue = new ArrayBlockingQueue<String>(capacity);
        queue.add("Reema");
        queue.add("Rahul");
        queue.add("Rita");
        queue.add("Ramesh");
        //peek() method will retrieve the head of the queue
        System.out.println("Head of queue : "+queue.peek());
        //peek() will not remove the head from the queue
        System.out.println("        Queue : "+queue);
    }
}

Output:

Head of queue : Reema
        Queue : [Reema, Rahul, Rita, Ramesh]

Example 2

import java.util.Queue;
import java.util.concurrent.ArrayBlockingQueue;
class Student {
    int marks;
    String name;
    public Student(int marks, String name) {
        this.marks = marks;
        this.name = name;
    }
   public String toString(){
        return this.name+" got "+ this.marks +" marks.";
   }
}
public class ArrayBlockingQueuePeekExample2 {
    public static void main(String[] args) {
        Student student1 = new Student(97,"Hinna");
        Student student2 = new Student(87,"Vinni");
        Student student3 = new Student(77,"Rima");
        int capacity =100;
        Queue<Student> queue = new ArrayBlockingQueue<Student>(capacity);
        queue.add(student1);
        queue.add(student2);
        queue.add(student3);
         for (Student xyz : queue){
             System.out.println(xyz);
         }
        System.out.println();
       System.out.println("Topper of the class is "+queue.peek().name);
    }
}

Output:

Hinna got 97 marks.
Vinni got 87 marks.
Rima got 77 marks.
Topper of the class is Hinna

Example 3

import java.util.concurrent.ArrayBlockingQueue;
public class ArrayBlockingQueuePeekExample3 {
    public static void main(String[] args) {
        int capacity =100;
        ArrayBlockingQueue<String> queue = new ArrayBlockingQueue<String>(capacity);
        queue.add("Reema");
        queue.add("Rahul");
        queue.add("Rita");
        queue.add("Ramesh");
        queue.clear();
        String val = queue.peek();
        System.out.println("Head of queue is : "+val);
    }
}

Output:

Head of queue is : null

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Java ArrayBlockingQueue peek() Method

Syntax:

Parameters:

Specified By:

Return Value:

Example 1

Example 2

Example 3

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