title: Java Collectors.groupingBy()---is List ordered?
body: <p>For the <code>Collectors.groupingBy()</code> that returns <code>Map&lt;K,List&lt;T&gt;&gt;</code> is it implied that the <code>List&lt;T&gt;</code> is in order that the stream is evaluated?</p>
  
  <p>I see no explicit description of the ordering of the list, whereas the concurrent version explicitly states no ordering. If it weren't ordered somehow, I'd expect it to be a Collection though, and I don't see what other ordering it could possibly be, other than order received.</p>
  
  <p>I'm hoping it's guaranteed that the last value in each list is the last value received for that group.</p>