Функции метода Object.clone()

public class Snake implements Cloneable {
    private Snake next, tmp;
    private char c;

    // Значение i == количеству сегментов
    Snake(int i, char x) {
        c = x;
        if(--i > 0)
            next = new Snake(i, (char) (x + 1));
    }

    void increment() {
        c++;
        if(next != null)
            next.increment();
    }

    public String toString() {
        String s = ":" + c;
        if(next != null)
            s += next.toString();
        return s;
    }

    @Override
    public Object clone() {
        Snake o = null;
        try {
            o = (Snake)super.clone();
        } catch(CloneNotSupportedException e) {
            System.err.println("Змея не может быть клонирована");
        }

        Snake tmp = next;

        while (tmp != null)
        {
            o.next = (Snake)tmp.clone();
            tmp = tmp.tmp;
        }

        return o;
    }
    public static void main(String[] args) {
        Snake s = new Snake(5, 'a');
        System.out.println("s = " + s);
        Snake s2 = (Snake)s.clone();
        System.out.println("s2 = " + s2);
        s.increment();
        System.out.println("after s.increment, s = " + s);
        System.out.println("after s.increment, s2 = " + s2);

    }
}

    @Override
    public Object clone() {
        Snake o = null;
        try {
            o = (Snake)super.clone();
        } catch(CloneNotSupportedException e) {
            System.err.println("Змея не может быть клонирована");
        }

        while (next != null)
        {
            o.next = (Snake)next.clone();
            next = next.next;
        }

        return o;
    }