title: Jackrabbit nt:folder nt:file exception
body: <p>i am trying to add a child node to a nt:folder node (rep:AuthorizableFolder node actually, but the same problem arises with other node types). In the lines below the folder node appears in the path as <strong>USUARIO-1311259687502</strong>.</p>
  
  <p>Saw your examples and some similar more, but the following line:</p>
  
  <pre><code>        **Node fileNode = folderNode.addNode(file.getName(), "nt:file");**
  </code></pre>
  
  <p>throws the following exception:</p>
  
  <p><strong>Exception in thread "main" javax.jcr.nodetype.ConstraintViolationException: No child node definition for lebAudio.mp3 found in node /rep:security/rep:authorizables/rep:users/USUARIO-1311259687502</strong></p>
  
  <p>Despite of having read some docu about node types (and understanding that nt:file is allowed as nt:folder child, and both are built-in types in Jackrabbit, so nothing special should be done) i do not understand what is wrong. Any idea?</p>
  
  <p>Thanks in advance, have a nice day!</p>