JDO defines XML MetaData in jdo files as well as orm files. As always with XML, the metadata must match the defined DTD/XSD for that file type. This section describes the content of the orm files. The content of jdo files can be found here. All orm files must contain a valid DTD/DOCTYPE specification. You can use PUBLIC or SYSTEM versions of these.
Here are a couple of examples valid for orm files with DTD specification
<!DOCTYPE orm PUBLIC "-//Sun Microsystems, Inc.//DTD Java Data Objects Mapping Metadata 3.0//EN" "http://java.sun.com/dtd/orm_3_0.dtd"> <!DOCTYPE orm SYSTEM "file:/javax/jdo/orm.dtd">
Here is an example valid for orm files with XSD specification
<?xml version="1.0" encoding="UTF-8" ?> <orm xmlns="http://java.sun.com/xml/ns/jdo/orm" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/jdo/orm http://java.sun.com/xml/ns/jdo/orm_3_0.xsd"> ... </orm>