Home/ Questions/Q 4614438
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-22T01:42:00+00:00

What is the meaning of web.xml id attribute of the web-app tag? Eclipse generated

  • 0

What is the meaning of web.xml id attribute of the web-app tag?

Eclipse generated it as id=”WebApp_ID”. I was using version the Servlet specification version 2.5, I switched to using 3.0, with the suggestion of this answer that doesn’t include that id.

Is it really necessary? What is the value supposed to be?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    The newer versions of the servlet spec use .xsd files with no further information on the id attribute, but if you go back to the older versions with .dtd, such as web_app_2_2.dtd, you find:

    The ID mechanism is to allow tools to
    easily make tool-specific references
    to the elements of the deployment
    descriptor. This allows tools that
    produce additional deployment
    information (i.e information beyond
    the standard deployment descriptor
    information) to store the non-standard
    information in a separate file, and
    easily refer from these tools-specific
    files to the information in the
    standard web-app deployment
    descriptor.

    For example, WebSphere Application Server used the id mechanism in its old bnd and ext files:

    web.xml:
<web-app id="WebApp_ID" ...

ibm-web-app-bnd.xmi:
<webappbnd:WebAppBinding ...
  <webapp href="WEB-INF/web.xml#WebApp_ID"/>

    (Thankfully, this is tool-friendly-but-developer-annoying use of id attributes is no longer necessary with the newer .xml file format for ibm-web-bnd/ext, but I digress.)

    • 0