Enterprise JavaBeans, Second Edition

The Document Header

All XML documents start with a few tags that provide general information about the document itself. The first tag specifies the version of XML that is in use:

<?xml version="1.0"?>

This tag identifies the document as an XML document that adheres to Version 1.0 of the XML specification.

The next tag specifies the DTD that defines the document:

<!DOCTYPE ejb-jar PUBLIC "-//Sun Microsystems, Inc.//DTD Enterprise
JavaBeans 1.1//EN" "http://java.sun.com/j2ee/dtds/ejb-jar_1_1.dtd">

This tag provides the URL from which you (or, more important, tools processing the deployment descriptor) can download the document. The DTD can be used to validate the XML document; this means that the EJB server deploying the bean can download the DTD and use it to prove that your deployment descriptor is correct (i.e., that it is organized correctly uses the right tag names, and that all the tags and attributes have appropriate parameters).

This tag also identifies the name of the document’s root element, which is ejb-jar. The <ejb-jar> tag marks the beginning of the document proper.