PHP mail form questions?

  1. Is using a php based mailform the best way to stop spambots?
    or is using java enough and as cross platform friendly(like on mac)?
  2. How would one set it up so that the person submitting the form
    will recieve a copy of their message as well for their records?
  3. Does the email validating happen clientside in the html form page
    or via php file upon submit?

sorry if this is basic stuff _ i did search first with no real answers
thanks for any help in advance
sky