In previous versions of OAuth2 it was possible to add a custom token granter by adding it to the xml configuration in the element.<
You need to add the default ones too, e.g. using a CompositeTokenGranter:
CompositeTokenGranter
List tokenGranters = getTokenGranters(); // implementation up to you tokenGranter = new CompositeTokenGranter(tokenGranters); endpoints.tokenGranter(tokenGranter);