How do I use ConcurrentHasMap forEach() method?

The forEach() method in ConcurrentHashMap is used for iteration over the entries in the map. The method takes a BiConsumer as an argument, which is a functional interface that represents an operation that accepts two input arguments and returns no result.

Here’s an example of how to use forEach() with a ConcurrentHashMap:

package org.kodejava.util.concurrent;

import java.util.concurrent.ConcurrentHashMap;

public class ConcurrentHashMapForEachExample {
    public static void main(String[] args) {
        // Create a new ConcurrentHashMap
        ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<>();

        // Add some key-value pairs
        map.put("One", 1);
        map.put("Two", 2);
        map.put("Three", 3);
        map.put("Four", 4);

        // Use forEach to iterate over the ConcurrentHashMap.
        // The BiConsumer takes a key (k) and value (v), and we're
        // just printing them here.
        map.forEach((k, v) -> System.out.println("Key: " + k + ", Value: " + v));
    }
}

Output:

Key: One, Value: 1
Key: Four, Value: 4
Key: Two, Value: 2
Key: Three, Value: 3

In the above example, forEach() is used to iterate over the entries of the map. For each entry, the key and value are printed. The forEach() method is often more convenient to use than an iterator, especially when you’re only performing a single operation (like print) for each entry in the map.

Author
Recent Posts

Wayan

Founder at Kode Java

Hi, I'm a passionate programmer based on the beautiful island of Bali. I specialize in Java, with hands-on experience in Spring, Hibernate/JPA, and MySQL. I'm currently working on a project I care deeply about, and your support—big or small—helps fuel my work (and my coffee ☕️).

If you like what I’m building, consider buying me a cup of coffee. Thanks a lot!

Leave a ReplyCancel reply