<!ELEMENT web-app
    icon?,
    display-name?,
    description?,
    distributable?,
    context-param*,
    filter*,
    filter-mapping*,
    listener*,
    servlet*,
    servlet-mapping*,
    session-config?,
    mime-mapping*,
    welcome-file-list?,
    error-page*,
    taglib*,
    resource-env-ref*,
    resource-ref*,
    security-constraint*,
    login-config?,
    security-role*,
    env-entry*,
    ejb-ref*,
    ejb-local-ref*
>