title: Get LocalDateTime based on year and week of year
body: <p>I have two integers: <code>year</code> and <code>week</code>. I would like to construct a <code>LocalDateTime</code> from these two values, where the date represents the first day of the particular week in the particular year.</p>
  
  <p>I already tried this:</p>
  
  <pre><code>LocalDateTime ldt = LocalDateTime.of(year, 1, 1, 0, 0).plusWeeks(week-1);
  </code></pre>
  
  <p>This does not give the correct result, because the first day of the year is not always the beginning of the first week of that year. I can not seem to figure out how to get the first day of the first week either.</p>
  
  <p>Is there any simple way to do this with the Date and Time API in Java 8?</p>
  
  <p>Note: I know I could also create a workaround with answers given <a href="https://stackoverflow.com/questions/28450720/get-date-of-first-day-of-week-based-on-localdate-now-in-java-8">here</a>, but this seems to far-fetched. Maybe it isn't, if so, let me know!</p>