title: Scala Map to Java HashMap
body: <p>I have a Scala function <code>f(s1: String, s2: String): Map[String,String]</code></p>
  
  <p>I want to allow a colleague coding in Java to call a Java method I'm writing:</p>
  
  <p><code>HashMap&lt;String, String&gt; f(String s1, String s2)</code></p>
  
  <p>This calls my Scala function.  What I've found, on the Java side, is that Scala has returned a <code>scala.collection.immutable.Map</code>.</p>
  
  <p>How do I make a Java HashMap out of it?  Or should I be doing something else?</p>