/URIs/dtds are looked up in each of the following contexts,
 stopping when a valid and readable resource is found:
 <ol>
 <li>In the local filesystem</li>
 <li>In the classpath</li>
 <li>Using the Apache xml-commons resolver (if it is available)</li>
 <li>In URL-space</li>
 </ol>
 </p>

 <p>See <a href="../../../../../org/apache/tools/ant/taskdefs/optional/XMLValidateTask.html" title="class in org.apache.tools.ant.taskdefs.optional"><code>XMLValidateTask</code></a> for an example of a task that has integrat