Client on Wildfly: how to get own access token?

My Java EE application running on Wildfly is a Keycloak Client with the option “Service Accounts Enabled” and “org.keycloak:keycloak-wildfly-adapter:8.0.2” on its classpath.

Now I want to authenticate to some other service, i.e. do something like this:
webTarget.request().header(“Authorization”, "Bearer "+KeycloakClient.getAccessToken());

But how? Is there such a thing as “KeycloakClient.getAccessToken()”? Please point me to some documentation, I can’t find it.