title: JPA Map<String,String> mapping with xml
body: <p>I am trying to define <strong>xml mapping</strong> for a <code>Map&lt;String,String&gt;</code> field. </p>
  
  <p>The entity class cannot be modified so I am using the XML variant of JPA mapping, but cannot figure out the proper syntax.</p>
  
  <p>Can someone explain how to write the JPA <strong>xml</strong> for this case - or explicitly state that this is impossible with xml but possible with annotations as mentioned in <a href="https://stackoverflow.com/questions/3393649/storing-a-mapstring-string-using-jpa">Storing a Map&lt;String,String&gt; using JPA</a> ...</p>
  
  <p>I will even appreciate to know that <em>this is impossible</em> - ideally when it comes with reference to the part of specification that states it.</p>