title: How to convert, group and sort java.util.List[java.util.Map[String, Object]]?
body: <p>I convert this:</p>
  
  <pre><code>import scala.collection.JavaConverters._
  import scala.collection.JavaConverters._
  val list:java.util.List[java.util.Map[String, Object]] = new java.util.ArrayList[java.util.Map[String, Object]]()
  val map1:java.util.Map[String, AnyRef] = new java.util.HashMap[String,AnyRef]()
  map1.put("payout", 3.asInstanceOf[AnyRef])
  list.add(map1)
  val map2:java.util.Map[String, AnyRef] = new java.util.HashMap[String, AnyRef]()
  map2.put("payout", 2.asInstanceOf[AnyRef])
  list.add(map2)
  val map3:java.util.Map[String, AnyRef] = new java.util.HashMap[String, AnyRef]()
  map3.put("payout", 2.asInstanceOf[AnyRef])
  list.add(map3)
  val map4:java.util.Map[String, AnyRef] = new java.util.HashMap[String, AnyRef]()
  map4.put("payout", 1.asInstanceOf[AnyRef])
  list.add(map4)
  println(list)
  val result = list.asScala
  //result Buffer({payout=3}, {payout=2}, {payout=2}, {payout=1})
  </code></pre>
  
  <p>And i wish:
  list.asScala.groupBy(_("payout")).toList save its ordering (sort by payout)
  but <code>.toList.sortBy(_._1)</code> throw error: 
  error: No implicit Ordering defined for java.lang.Object.</p>
  
  <pre><code>val result = list.groupBy(_("payout")).toList.sortBy(_._1)
  </code></pre>