CopyOnWriteArraySet forEach() method in Java with Examples

Last Updated : 19 Mar, 2019

The forEach() method of CopyOnWriteArraySet is an in-built function in Java which is used to traverse each element in this Set.

Syntax:

public void forEach (Consumer<E> action)

Parameters: This method takes a parameter action which represents the action to be performed for each element.

Return Value: This method does not returns anything.

Exceptions: This method throws NullPointerException if the specified action is null.

Below program illustrates the forEach() function of CopyOnWriteArraySet class:

Example 1:

// Java Program to illustrate the CopyOnWriteArraySet 
// forEach() method in Java 
  
import java.util.concurrent.CopyOnWriteArraySet; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create object of CopyOnWriteArraySet 
        CopyOnWriteArraySet<Integer> ArrSet 
            = new CopyOnWriteArraySet<Integer>(); 
  
        // Add elements 
        ArrSet.add(2); 
        ArrSet.add(3); 
        ArrSet.add(4); 
        ArrSet.add(7); 
        ArrSet.add(8); 
  
        // print CopyOnWriteArraySet 
        System.out.println("CopyOnWriteArraySet: "
                           + ArrSet); 
        System.out.println("Traversing this Set: "); 
  
        // Traverse this set using forEach() method 
        ArrSet.forEach((n) -> System.out.println(n)); 
    } 
} 

Output:

CopyOnWriteArraySet: [2, 3, 4, 7, 8]
Traversing this Set: 
2
3
4
7
8

Example 2:

// Java Program to illustrate the CopyOnWriteArraySet 
// forEach() method in Java 
  
import java.util.concurrent.CopyOnWriteArraySet; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Create object of CopyOnWriteArraySet 
        CopyOnWriteArraySet<String> ArrSet 
            = new CopyOnWriteArraySet<String>(); 
  
        // Add elements 
        ArrSet.add("GeeksforGeeks"); 
        ArrSet.add("Geeks"); 
        ArrSet.add("Computer Science"); 
        ArrSet.add("Portal"); 
        ArrSet.add("Gfg"); 
  
        // Print CopyOnWriteArraySet 
        System.out.println("CopyOnWriteArraySet: "
                           + ArrSet); 
        System.out.println("Traversing this Set: "); 
  
        // Traverse this set using forEach() method 
        ArrSet.forEach((n) -> System.out.println(n)); 
    } 
} 

Output:

CopyOnWriteArraySet: [GeeksforGeeks, Geeks, Computer Science, Portal, Gfg]
Traversing this Set: 
GeeksforGeeks
Geeks
Computer Science
Portal
Gfg

Reference: https://docs.oracle.com/javase/9/docs/api/java/util/concurrent/CopyOnWriteArraySet.html#forEach-java.util.function.Consumer-

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