title: JAXB: how to marshall HashMap<String, HashMap<String, String>>?
body: <p>I have a complex structure of data, that can describe by HashMap inside HashMap. I need create XML file of structure. Like this:</p>
  <pre><code>&lt;map&gt;
      &lt;key1&gt;
          &lt;map&gt;
             &lt;key1&gt;someString1&lt;/key1&gt;
             &lt;key2&gt;someString2&lt;/key2&gt;
          &lt;/map&gt;
      &lt;/key1&gt;
      &lt;key2&gt;
          &lt;map&gt;
             &lt;key1&gt;someString1&lt;/key1&gt;
             &lt;key2&gt;someString2&lt;/key2&gt;
          &lt;/map&gt;
      &lt;/key2&gt;
  &lt;/map&gt;
  </code></pre>
  <p>But I noticed, JAXB has some problems with it. Is there any way to make XML from maps?</p>