title: jdbc4.CommunicationsException: Communications link failure
body: <p>Did someone face such an error happening in case of some queries execution? (<em>jdbc4.CommunicationsException: Communications link failure</em>)</p>
  
  <p>Generally, this exception means some problem of communication between application and mysql. And you can find a lot of suggestions posted regarding possible reason. </p>
  
  <p>Nothing helped in our case, and after several hours of investigation it turned out that the reason can be completely other.<br>
  Maybe the answer below will save someones time :) </p>