web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         version="3.0">

    <module-name>servlet-authz-app</module-name>

    <security-constraint>
        <web-resource-collection>
            <web-resource-name>All Resources</web-resource-name>
            <url-pattern>/*</url-pattern>
        </web-resource-collection>
        <auth-constraint>
            <role-name>user</role-name>
            <role-name>admin</role-name>
            <role-name>user_premium</role-name>
        </auth-constraint>
    </security-constraint>
        <security-constraint>
            <web-resource-collection>
                <web-resource-name>Public Resource</web-resource-name>
                <url-pattern>/public-html.html</url-pattern>
            </web-resource-collection>
        </security-constraint>

    <login-config>
        <auth-method>KEYCLOAK</auth-method>
        <realm-name>servlet-authz</realm-name>
    </login-config>

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

    <security-role>
        <role-name>user</role-name>
    </security-role>

    <security-role>
        <role-name>user_premium</role-name>
    </security-role>

    <error-page>
        <error-code>403</error-code>
        <location>/accessDenied.jsp</location>
    </error-page>

</web-app>