title: Get date-time in seconds from current date
body: <p>Need to get date-time in seconds from current date.
  Want to add 2 days from current date-time and get value of 7 PM of result day.</p>
  
  <p>I.E. 
  Current date-time is 1 January, 7:05 PM OR 6:55 PM, I should get value of 3 January, 7:00 PM in seconds. </p>
  
  <p>P.S. - Can't use JODA Time &amp; Java 8.</p>