title: How to convert LocalDateTime to GregorianCalendar?
body: <p>Why is it possible to pass a <code>LocalDateTime</code> object into the <code>ZonedDateTime.from()</code> method, if it's not possible to parse a simple <code>DateTime</code>, as follows?</p>
  
  <pre><code>@Test
  public void test() throws Exception {
      GregorianCalendar.from(ZonedDateTime.from(LocalDateTime.parse("2016-08-31T23:00:59")));
  }
  </code></pre>
  
  <p>Result:</p>
  
  <pre><code>java.time.DateTimeException: Unable to obtain ZonedDateTime from TemporalAccessor: 2016-08-31T23:00:59 of type java.time.LocalDateTime
      at java.time.ZonedDateTime.from(ZonedDateTime.java:565)
  </code></pre>