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The forEach() method of CopyOnWriteArrayList performs the given action for each element of the Iterable until all elements have been processed or the action throws an exception. Syntax:

public void forEach (Consumer<E> action)

Parameters: This method takes a parameter action which represents the action to be performed for each element. Returns: This method does not returns anything. Exceptions: This method throws NullPointerException if the specified action is null. Below program illustrates the forEach() function of CopyOnWriteArrayList class : Program 1:

Java

// Java Program to illustrate the CopyOnWriteArrayList
// forEach() method in Java

import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;

public class GFG {
    public static void main(String[] args)
    {

        // Create object of CopyOnWriteArrayList
        CopyOnWriteArrayList<Integer> ArrLis
            = new CopyOnWriteArrayList<Integer>();

        // Add elements
        ArrLis.add(2);
        ArrLis.add(3);
        ArrLis.add(4);
        ArrLis.add(7);

        // Print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList: "
                           + ArrLis);

        System.out.println("Traversing this List : ");

        // Traverse this queue using forEach() method
        ArrLis.forEach((n) -> System.out.println(n));
    }
}

Output:

CopyOnWriteArrayList: [2, 3, 4, 7]
Traversing this List : 
2
3
4
7

Program 2:

Java

// Java Program to illustrate the CopyOnWriteArrayList
// forEach() method in Java

import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;

public class GFG {
    public static void main(String[] args)
    {

        // Create object of CopyOnWriteArrayList
        CopyOnWriteArrayList<String> ArrLis
            = new CopyOnWriteArrayList<String>();

        // Add elements
        ArrLis.add("Geeks");
        ArrLis.add("Gfg");
        ArrLis.add("Portal");
        ArrLis.add("geeksforgeeks");

        // Print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList: "
                           + ArrLis);

        System.out.println("Traversing this List : ");

        // Traverse this queue using forEach() method
        ArrLis.forEach((n) -> System.out.println(n));
    }
}

Output:

CopyOnWriteArrayList: [Geeks, Gfg, Portal, geeksforgeeks]
Traversing this List : 
Geeks
Gfg
Portal
geeksforgeeks

Reference: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CopyOnWriteArrayList.html#forEach-java.util.function.Consumer-

CopyOnWriteArrayList forEach() method in Java with Examples

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