Safe access to list element by index

It is necessary to eliminate returning null when the requested element is missing, replacing it with a more reliable and type-safe mechanism, as well as improving the interface contract for proper handling of such scenarios.

package com.narozhnyi;

public interface Node<T> {
    // add element
    boolean add(T val);

    // retrieve element by index
    T get(int index);
}

@Override
public T get(int index) {
    // initialize counter = 0
    // traverse the list until next is null
    int pos = 0;
    for (int step = 0; step < index; step++) {
        if (pos == index) {
            return value;
        }
        pos++;
    }
    return null;
}