what will the following code do $?$

public void fun$($Node a$)\{$

if$($size $==0)$

head $=$ a;

else$\{$

Node t$,$ inst;

for$($inst $=$ head; $($t $=$ inst.getNext$())!=$ null; inst $=$ t$)$

;

inst.setNext$($a$)$; $//$ Add the new node at the end

$\}$

size$++$;

$\}$