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">
    <servlet>
        <servlet-name>Resteasy</servlet-name>
        <servlet-class>org.jboss.resteasy.plugins.server.servlet.HttpServlet30Dispatcher</servlet-class>
        <init-param>
            <param-name>javax.ws.rs.Application</param-name>
            <param-value>org.keycloak.example.demo.DemoApplication</param-value>
        </init-param>
        <init-param>
            <param-name>resteasy.servlet.mapping.prefix</param-name>
            <param-value>/rest</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
        <async-supported>true</async-supported>
    </servlet>

    <servlet-mapping>
        <servlet-name>Resteasy</servlet-name>
        <url-pattern>/rest/*</url-pattern>
    </servlet-mapping>

    <!--
    <security-constraint>
        <web-resource-collection>
            <url-pattern>/*</url-pattern>
        </web-resource-collection>
        <user-data-constraint>
            <transport-guarantee>CONFIDENTIAL</transport-guarantee>
        </user-data-constraint>
    </security-constraint> -->

</web-app>