title: Taxonomy hierarchy representation format
body: <p>We are planning to integrate a hierarchical taxonomy in our software solution. (Java based)</p>
  
  <p><strong>Is there a standardized (and easy to use) format to represent hierarchical taxonomies?</strong> A format which would the common exchange format used by different taxonomy editors?</p>
  
  <p>I have been looking at OWL (RDF), PMML... but those are either quite complex, or do not really seem be fit for this purpose.</p>
  
  <p>To give a simple example. We would like to represent a tree of concepts. Attached to each concept there would be some kind of data object (in brackets)</p>
  
  <pre><code>Vehicles (category := 'V')
   |-&gt; Car (code := 1)
   |    |-&gt; Petrol (code := 2 &amp;&amp; car_code := 'petrol')
   |    |-&gt; Electical (code := 2 &amp;&amp; car_code := 'electrical')
   |-&gt; Plane (code := 1)
  </code></pre>
  
  <p>We could of develop our own XML format using a serialization library like Xstream. But if there is a good standard - which is well supported by Java, I would prefer to use it. </p>