title: Convert elapsed time between epoch time and current moment to ISO 8601 duration with Java
body: <p>I have milliseconds since 1970 january 1 UTC (Epoch time). </p>
  
  <pre><code>1512431637067
  </code></pre>
  
  <p>I need to convert this to something like (ISO-8601 duration). This will be based off current today's date.</p>
  
  <pre><code>P5M4D
  </code></pre>
  
  <p>Any idea how to do this in a simple way using java code?</p>