title: XML validation - known and unknown attributes optional?
body: <p>please tell me whether it is possible and, if possible. How to declare in the xsd, that all attributes in my xml are optional. I cannot declare all attributes, because my xml has different number of attributes, both known and unknown.</p>
  
  <pre><code>        schema = factory.newSchema(new StreamSource(xsdFileInputStream));
          Validator validator = schema.newValidator();
          validator.validate(new StreamSource(new StringReader(xmlString)));
  </code></pre>
  
  <p>Thanks.</p>