Interview Question for Software Development Engineer at Amazon.com:

public void Merge(LinkList list1, LinkList list2) {
        if (list1.head == null && list2.head == null) {
            System.out.println("Empty list"); //checks if list is empty
        }
        if (list1.head == null) {
            list2.printList();
        }
        if (list2.head == null) {
            list1.printList();
        }
        LinkList list3 = new LinkList();
        Node a = list1.head;
        Node b = list2.head;
        while (a != null && b != null) {
            if (a.value < b.value) {
                list3.insert(a.value);
                a = a.next;
            } else if (a.value > b.value) {
                list3.insert(b.value);
                b = b.next;
            } else if (a.value == b.value){ //inserts only unique value to the merged list
                list3.insert(a.value);
                a = a.next;
                b = b.next;
            }
        }
        if (a == null) {
            while (b != null) {
                list3.insert(b.value);
                b = b.next;
            }
        }
        if (b == null) {
            while (a != null) {
                list3.insert(a.value);
                a = a.next;
            }
        }
        list3.printList();
    }