let is being placed into service.

 <p>
 The servlet container calls the <code>init</code> method exactly once after instantiating the servlet. The
 <code>init</code> method must complete successfully before the servlet can receive any requests. The container will
 ensure that actions performed in the <code>init</code> method will be visible to any threads that subsequently call
 the <code>service</code> method according to the rules in JSR-133 (i.e. there is a 'happens before' relationship
 between <code>i