Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;

public class Main {

    public static void main(String[] args) {
        List<Integer> numbers = new ArrayList<Integer>();

        for (Integer i : Arrays.asList(0, 1, 2, 3, 4, 5, 6, 7))
            numbers.add(i);
        printList(numbers); // 0,1,2,3,4,5,6,7

        // replaces each element with twice its value
        for (int index = 0; index < numbers.size(); index++) {
            numbers.set(index, numbers.get(index) * 2);
        }
        printList(numbers);

        // does nothing because list is not being changed
        for (Integer number : numbers) {
            number++;
        }
        printList(numbers);

        // same as above -- just different syntax
        for (Iterator<Integer> iter = numbers.iterator(); iter.hasNext();) {
            Integer number = iter.next();
            number++;
        }
        printList(numbers);

        for (ListIterator<Integer> iter = numbers.listIterator(); iter.hasNext();) {
            Integer number = iter.next();
            iter.add(number + 1);
        }
        printList(numbers);

        for (Iterator<Integer> iter = numbers.iterator(); iter.hasNext();) {
            Integer number = iter.next();
            if (number % 2 == 0) // if number is even
                iter.remove(); // remove it from the collection
        }
        printList(numbers); // 1,3,5,7,9,11,13,15

        // ListIterator<?> has a "set" method to replace elements
        for (ListIterator<Integer> iter = numbers.listIterator(); iter.hasNext();) {
            Integer number = iter.next();
            iter.set(number / 2); // divide each element by 2
        }
        printList(numbers); // 0,1,2,3,4,5,6,7

        // Use Java 8 Lambda
        List<Integer> list = numbers;
        list.stream().forEach(elem -> System.out.println("element " + elem));

    }

    public static void printList(List<Integer> numbers) {
        System.out.println(numbers);
    }
}