Special Edition Using Java™ 2 Enterprise Edition

Basic XML Syntax

An XML page consists of two sections: a prolog and the root element. You can't have more than one root element—all the data in the XML document must be enclosed by a single root element. The XML prolog begins with an XML processing instruction identifying the document as an XML document. XML processing instructions begin with <?. Usually, the tag looks like this:

<?xml version="1.0"?>

Next, when you create an XML page, you have the option of specifying a Document Type Definition (DTD) that defines what tags are permitted in the XML page. DTDs let you create standard definitions of XML pages. You can then use an XML validator to check an XML page to make sure it conforms to its DTD. Use the <!DOCTYPE declaration to specify the ...