title: How to set multiple Namespace, one of them without prefix (JDom)
body: <p>I need to set a namespace, I hope someone can help me.</p>
  
  <p>That is what I need:</p>
  
  <pre><code>&lt;Document xmlns="urn:iso:std:iso:20022:tech:xsd:pain.001.001.03"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"&gt;
  </code></pre>
  
  <p>I try to do this that way:</p>
  
  <pre><code>            Namespace ns1 = Namespace.getNamespace("urn:iso:std:iso:20022:tech:xsd:pain.001.001.03");
          Namespace ns2 = Namespace.getNamespace("xsi", "http://www.w3.org/2001/XMLSchema-instance");
          Element root = new Element("Document");
          root.addNamespaceDeclaration(ns2);
          root.addNamespaceDeclaration(ns1);
  </code></pre>
  
  <p>But I get this exception:</p>
  
  <blockquote>
    <p>The namespace xmlns="urn:iso:std:iso:20022:tech:xsd:pain.001.001.03"
    could not be added as a namespace to "Document": The namespace prefix
    "" collides with the element namespace prefix</p>
  </blockquote>
  
  <p>Thanks</p>