Traversing elements in the collection interface

CollectionInterfaceTraversalMethods.java

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

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

        Collection<Integer> collection1 = new ArrayList<>(List.of(1, 2, 3, 4, 5, 6));

        // 1- using the iterator method
        Iterator<Integer> iterator = collection1.iterator();
        while (iterator.hasNext()) {
            Integer currValue = iterator.next();
            System.out.print(currValue);

            // you can remove elements using iterator
            //  iterator.remove();
        }

        System.out.println();

        // 2- for each method
        for (int n : collection1) {
            System.out.print(n);
            // you can't remove elements inside for each method
            // this will throw an exception
            // collection1.remove(n);
        }

        System.out.println();

        // 3- iterate and perform an action
        collection1.forEach(System.out::print);

        System.out.println();

        // another example to print even numbers:
        collection1.forEach(e -> {
            if (e % 2 == 0) {
                System.out.print(e);
            }
        });
    }
}