As described in the MetaData Reference, JPOX accepts standard JDO2 metadata, namely jdo files as well as orm files for specifying the persistence of classes. JDO also allows Named Queries to be specified in a jdoquery file. As always with XML, the metadata must match the defined DTD/XSD for that file type. This section describes the content of the jdoquery files. All jdoquery files must contain a valid DTD/DOCTYPE specification. You can use PUBLIC or SYSTEM versions of these.

Here are a few examples valid for jdoquery files eith DTD specification

<!DOCTYPE jdoquery PUBLIC
    "-//Sun Microsystems, Inc.//DTD Java Data Objects Query Metadata 2.0//EN"
    "http://java.sun.com/dtd/jdoquery_2_0.dtd">


<!DOCTYPE jdoquery SYSTEM "file:/javax/jdo/jdoquery.dtd">

Here is an example valid for jdoquery files with XSD specification

<?xml version="1.0" encoding="UTF-8" ?>
<jdo xmlns="http://java.sun.com/xml/ns/jdo/jdo"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/jdo/jdoquery
        http://java.sun.com/xml/ns/jdo/jdoquery_2_0.xsd">
    ...
</jdo>

Your MetaData should match either the DTD or the XSD specification.