title: why Session attributes are officially not thread safe in Servlet?
body: <p>I am reading some servlet text regarding scope of attributes in Java servlet. In the text, the author wrote:
  "<code>Session attributes are officially not thread safe.</code>"</p>
  
  <p>This confused me because I thought that one user only has a specific session, no one can access of the others. If so, session attributes are thread safe. Or am I misunderstanding something??</p>