title: How do I get the currently used locale from Spring MVC?
body: <p>I have the following form.</p>
  
  <pre><code>&lt;form id="langForm" action="" method="get"&gt;
      &lt;select name="lang" id="lang" class="styled" onchange="this.form.submit();"&gt;
          &lt;option value="pl" ${param.lang == 'pl' ? 'selected' : ''} &gt;PL&lt;/option&gt;
          &lt;option value="en" ${param.lang == 'en' ? 'selected' : ''} &gt;EN&lt;/option&gt;
      &lt;/select&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>Spring MVC sets the language parameter and takes care about i18n/l10n. I would like to change the <code>${param.lang}</code> to let it obtain the current user language from session by Spring MVC, because the <code>lang</code> parameter is not necessarily present in every request. How can I achieve this?</p>