public class ListRecursion {
    public static void main(String[] args) {
	
	List2 list = new List2(); 
	list.display();
	
	list.add("A"); list.display();
	list.add("B"); list.display();
	list.add("C"); list.display();
	
	list.del("A"); list.display();
	list.del("B"); list.display();
	list.del("C"); list.display();
    }
}

class List2 {
    
    private ListNode head;
    public List2() { }
    
    // Add an element to end of list:
    public void add(Object o) {
	head = add(o, head);
    }
    
    // Recursive add helper:
    private ListNode add(Object o, ListNode n) {
        if (n == null)
	    return new ListNode(o, n);
        else {
	    n.next = add(o, n.next);
	    return n;
        }
    }
    
    // Remove 1st occurrence of an element from list:
    public void del(Object o) {
	head = del(o, head);
    }

    // Recursive remove helper:
    private ListNode del(Object o, ListNode n) {
	if (n == null)
	    return n;
        if (o.equals(n.item))
            return n.next;
        else {
	    n.next=del(o,n.next);
	    return n;
	}
    } 
    
    // Return description of list:
    public String toString() {
	return head.toString();
    }
    
    // Print list:
    public void display() {
	System.out.println(head);
    }
    
    // Using an inner class to skip getters/setters:
    private class ListNode {
	public Object item;
	public ListNode next;
	public ListNode(Object o, ListNode n) {
	    item = o;
	    next = n;
	}
	public String toString() {
	    String temp = item.toString();
	    if (next != null) 
		temp += " " + next.toString();
	    return temp;
	}
    }
}

/* Output:
   null
   A
   A B
   A B C
   B C
   C
   null
*/