  An even (resp. odd) lollipop is the coalescence of a cycle of even (resp.
odd) length and a path with pendant vertex as distinguished vertex. It is known
that the odd lollipop is determined by its spectrum and the question is asked
by W. Haemers, X. Liu and Y. Zhang for the even lollipop. We revisit the proof
for odd lollipop, generalize it for even lollipop and therefore answer the
question. Our proof is essentially based on a method of counting closed walks.
