(Java) lab 5.1 List

public class List {
    private static class Node {
        String data;
        Node pPrev;
        Node pNext;

        public Node(String data) {
            this.data = data;
            this.pPrev = null;
            this.pNext = null;
        }
    }

    private Node head;
    private Node tail;
    private int length = 0;

    public List() {
        head = null;
        tail = null;
    }

    public int getLength() {
        return this.length;
    }

    public void addElem(final String data) {
        Node temp = new Node(data);
        if (head == null) {
            head = temp;
        } else {
            if (tail == null) {
                head.pNext = temp;
                tail = temp;
                tail.pPrev = head;
            } else {
                tail.pNext = temp;
                temp.pPrev = tail;
                tail = temp;
            }
        }
        length++;
    }

    public void deleteElem(final int index) {
        boolean isDeleted = false;

        if (index == 0) {
            if (head.pNext != null) {
                head = head.pNext;
            }
            head.pPrev = null;
            isDeleted = true;
        }
        else {
            if (index == length - 1) {
                tail = tail.pPrev;
                tail.pNext = null;
                isDeleted = true;
            }
        }

        if (!isDeleted) {
            Node temp;
            int counter;
            if (index <= length - 1 - index) {
                temp = head;
                counter = 0;
                while (counter != index) {
                    temp = temp.pNext;
                    counter++;
                }
            } else {
                temp = tail;
                counter = length - 1;
                while (counter != index) {
                    temp = temp.pPrev;
                    counter--;
                }
            }
            temp.pPrev.pNext = temp.pNext;
            temp.pNext.pPrev = temp.pPrev;
        }
        System.out.println("\n|||ЭЛЕМЕНТ УСПЕШНО УДАЛЁН|||\n");
        length--;
    }

    public void reverse() {
        Node fromHead = head;
        Node fromTail = tail;
        String temp;
        int counter = 0;
        while (counter != (length / 2)) {
            temp = fromHead.data;
            fromHead.data = fromTail.data;
            fromTail.data = temp;
            fromHead = fromHead.pNext;
            fromTail = fromTail.pPrev;
            counter++;
        }
    }

    public String printList() {
        StringBuilder str = new StringBuilder();
        Node temp = head;
        int counter = 0;
        str.append("\n|||СПИСОК|||\n\n");
        while (counter != length) {
            str.append(counter).append(".  ").append(temp.data).append("\n");
            temp = temp.pNext;
            counter++;
        }
        return str.toString();
    }

    public boolean isEmpty() {
        return head == null;
    }
}