See https://novotnyr.github.io/scrolls/oauth-oidc-keycloak-spring-boot-6-client-credentials/
OAuth 2.0 Client Credentials Flow
https://novotnyr.github.io/scrolls/oauth-oidc-keycloak-spring-boot-6-client-credentials/
OAuth 2.0 Client Credentials Flow
https://novotnyr.github.io/scrolls/oauth-oidc-keycloak-spring-boot-6-client-credentials/