title: Is there a direct way to convert Map<String, List<String>> into a JSON String (using javax.json library)
body: <p>Lets assume I have the following Map</p>
  
  <pre><code>Map&lt;String, List&lt;String&gt;&gt; map = new HashMap&lt;&gt;();
  
  List&lt;String&gt; list = new ArrayList&lt;&gt;();
  list.add("First in list");
  list.add("Second in list");
  
  map.put("First in map", list);
  </code></pre>
  
  <p>So how can I convert it in a direct way to a JSON String using <strong>javax.json</strong> library?</p>