[keycloak-user] Obtain Google Token

Hey guys! I've been trying since a few days to make a rest-call to '/realms/myrealm/broker/google/token' from my Java-code. But when I send the request, the response says that the token is invalid. I have no clue what token to use. Can anybody please describe the flow of how to obtain the right tokens, or post some examples how to solve the problem. I looked at the example on GitHub ( https://github.com/keycloak/keycloak/tree/master/examples/broker/facebook...) but this example don't fit my needs because it is client-side. Any help would be appreciated, thanks! Thank you, Andreas