LList.java

import java.util.*;

public class LList implements MyList {
  private MyNode head;
  private int size;
  
  public LList() {
    size = 0;
  }
  
  public void add(Object item) {
    if (head == null) {
      head = new MyNode(item, null);
    } else {
      MyNode current = head;
      while (true) {
        if (current.getNext() == null) {
          break; 
        }
        current = current.getNext(); 
      }
      current.next = new MyNode(item, null);
    }
    size++;
  }
  
  public void add(int i, Object item) {
    
  }
  
  public Object get(int index) {
    if (index < 0 || index >= size()) {
      throw new IndexOutOfBoundsException();
    }
    
    MyNode current = head;
    for (int i = 0; i < index; i++) {
      current = current.getNext();
    }
    
    return current.getData();
  }
  
  public void remove(int i) {
    
  }
  
  public void set(int i, Object item) {
    
  }
  
  public int size() {
    return size;
  }
  
  private class MyNode {
    private Object data;
    private MyNode next;
    
    public MyNode(Object d, MyNode n) {
      data = d;
      next = n;
    }
    
    public Object getData() {
      return data;
    }
    
    public MyNode getNext() {
      return next; 
    }
  }
  
  public Iterator iterator() {
    return new LListIterator(head);
  }
  
  private class LListIterator implements Iterator {
    
    private MyNode current;
    
    public LListIterator(MyNode head) {
      current = head;
    }
    
    public Object next() {
      if (current == null) {
        throw new NoSuchElementException();
      }
      
      Object data = current.getData();
      current = current.getNext();
      return data;
    }
    
    public boolean hasNext() {
      return current != null;
    }
  }
}

LListTest.java

public class LListTest {
  
  public static void main(String[] args) {    
    LList l = new LList();
    l.add("A");
    l.add("B");
    l.add("C");
    
    Iterator it = l.iterator();
    System.out.println(it.next());
    System.out.println(it.next());  
    System.out.println(it.next()); 
    it.remove();
    
    while (it.hasNext()) {
      System.out.println(it.next()); 
    }
    
    for (Object el : l) {
      System.out.println(el);
    }

  }
  
}

MyList.java

public interface MyList extends Iterable {
   public void add(Object item);
   
   public void add(int i, Object item);
   
   public Object get(int i);
   
   public void remove(int i);
   
   public void set(int i, Object item);
   
   public int size();
}