<dependency>
    <groupId>org.keycloak</groupId>
    <artifactId>keycloak-spring-boot-starter</artifactId>
</dependency>
<dependency>
    <groupId>org.keycloak</groupId>
    <artifactId>keycloak-spring-security-adapter</artifactId>
</dependency>
<dependency>
    <groupId>org.keycloak</groupId>
    <artifactId>keycloak-tomcat8-adapter</artifactId>
</dependency>

keycloak.enabled=true
keycloak.realm=test
keycloak.auth-server-url=http://localhost:8080/auth
keycloak.ssl-required=external
keycloak.resource=rest
keycloak.bearer-only=true
keycloak.credentials.secret=<secret>
keycloak.principal-attribute=preferred_username
keycloak.security-constraints[0].authRoles[0]=application
keycloak.security-constraints[0].securityCollections[0].name=spring secured api
keycloak.security-constraints[0].securityCollections[0].patterns[0]=/api/**

management.security.enabled=false

POST /auth/realms/test/protocol/openid-connect/token HTTP/1.1
Host: localhost:8080
Cache-Control: no-cache
Postman-Token: <postman token>
Content-Type: application/x-www-form-urlencoded

grant_type=password&client_id=postman&username=root&password=12345678

GET /api/product HTTP/1.1
Host: localhost:18888
Authorization: Bearer <keycloak token from the request above>
Cache-Control: no-cache
Postman-Token: <postman token>

{
    "timestamp": <timestamp>,
    "status": 401,
    "error": "Unauthorized",
    "message": "Full authentication is required to access this resource",
    "path": "/api/product"
}