An authorization rule that determines who is permitted to access a Web resource collection.

In advanced Java, particularly in the context of web development using technologies like Java EE (Enterprise Edition), an authorization constraint refers to a security mechanism that controls access to specific resources or actions based on the identity and roles of the user.

Authorization constraints are typically defined in the deployment descriptor of a Java EE application, specifically in the web.xml file. The constraints specify which roles or users are allowed to access certain parts of the application. This helps in enforcing security policies and ensuring that only authorized users can perform certain actions or access specific resources.

For example, you might have a web application where only users with the “admin” role are allowed to access the administration panel. In the web.xml file, you would define an authorization constraint that restricts access to the “/admin” URL pattern to users with the “admin” role.

Here’s a simplified example of how an authorization constraint might be defined in web.xml:

xml

<web-app>

    <!-- Other configurations -->
    <security-constraint>

        <web-resource-collection>

            <web-resource-name>Admin Panel</web-resource-name>

            <url-pattern>/admin/*</url-pattern>

        </web-resource-collection>

        <auth-constraint>

            <role-name>admin</role-name>

        </auth-constraint>

    </security-constraint>
    <!-- Other configurations -->

</web-app>

In this example, the <security-constraint> element defines a constraint for the “/admin/*” URL pattern, specifying that only users with the “admin” role (defined in <role-name>admin</role-name>) are authorized to access these resources.