As mentioned in docs:
https://www.keycloak.org/docs/4.3/securing_apps/index.html#_java_adapter_...
The initial config file can be obtained from the the admin console. This
can be done by opening the admin console, select Clients from the menu and
clicking on the corresponding client. Once the page for the client is
opened click on the Installation tab and select Keycloak OIDC JSON
*Is there a REST API to obtain this json file?*