Confusion about reference variable

Question

Still, I am sometimes an incurable complete newbie. The code A works but I feel repeating same comparisons is somehow awkward. But, much simpler code B fails in inserting a new node in a tree. Could you explain what is happening here in Java backstage?
//[code A]
// code that works
while (p != null) {
  prev = p;
  if (p.compareTo(newnode) < 0){
    p = p.right;
  else{
    p = p.left;
if (prev.compareTo(newnode) < 0){
  prev.right = newnode;
else{
  prev.left = newnode;
//[code B]
// code that fails
while (p != null) {
  if (p.compareTo(newnode) < 0){
    p = p.right;
  else{
    p = p.left;
p = newnode; // p is original p, p.right or p.left
             // == prev, prev.right or prev.left on above code

Answer 1

Case A:
you hold the reference of the last node in "prev". so after completing the traversal ur "p" becomes null and "prev" hold the exact leaf position to add the new node.
for which u used prev.right or prev.left to store the reference of the new node.
Case B:
U traverse correctly but do not hold the reference of the leaf , which will store the new node.
In this case u will never be able to add a new node. as u had lost the reference which will store the new node.
I think u are confused,bcoz u think that in case of b , "p" is the right position to store the new node and assighing new node to p will work.
but think when u set new node reference to p that reference is not hold by any of the tree node (as reference are stored in <leaf>.right or <leaf>.left).
I think this will make u understand the holding of reference in the tree.