Java size()

In Java, size() method returns the number of elements currently present in a collection like a queue, helping determine how many items are stored at any given moment.

Syntax

queue.size()

Parameters:

The size() method does not take any parameters.

Return value:

• Returns an integer representing the number of elements in the queue.

Example 1: Get Queue Length using Java size()

In this example, the size() method in Java is used to find the number of elements present in a queue:

import java.util.LinkedList;
import java.util.Queue;

public class QueueSizeExample {
  public static void main(String[] args) {
    Queue<String> queue = new LinkedList<>();

    queue.add("Apple");
    queue.add("Banana");
    queue.add("Cherry");

    System.out.println("Queue size: " + queue.size());
  }
}

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The output of this code is:

Queue size: 3

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Example 2: Check Queue Size Before Processing

In this example, the size() method in Java is used to verify if a queue contains elements before processing them:

import java.util.LinkedList;
import java.util.Queue;

public class QueueSizeCheckExample {
  public static void main(String[] args) {
    Queue<Integer> numbers = new LinkedList<>();

    numbers.add(10);
    numbers.add(20);
    numbers.add(30);

    if (numbers.size() > 0) {
      System.out.println("Queue has " + numbers.size() + " elements. Processing...");
      while (!numbers.isEmpty()) {
        System.out.println("Removed: " + numbers.remove());
      }
    } else {
      System.out.println("Queue is empty. Nothing to process.");
    }
  }
}

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The output of this code is:

Queue has 3 elements. Processing...
Removed: 10
Removed: 20
Removed: 30

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