I am running Keycloak in a docker container and wrote a SPI, which provides some custom rest endpoints. I compiled the code, placed the jar in the Keycloak providers folder and everything works fine. Now I want to make a global exception handler and I can not find anything in the documentation or online that works.

I wrote a GlobalExceptionMapper like this:

import com.b.keycloak.presenter.ErrorPresenter;
import jakarta.ws.rs.core.Response;
import jakarta.ws.rs.ext.ExceptionMapper;
import jakarta.ws.rs.ext.Provider;
import org.jboss.logging.Logger;

@Provider
public class GlobalExceptionMapper implements ExceptionMapper<Exception> {

  private static final Logger logger = Logger.getLogger(GlobalExceptionMapper.class);

  @Override
  public Response toResponse(Exception exception) {
    logger.error("Exception occurred: ", exception);

    if (exception instanceof RuntimeException) {
      return Response.status(Response.Status.BAD_REQUEST)
          .entity(
              ErrorPresenter.makeError(exception.getMessage(), "resolution", "endpoint", "method"))
          .build();
    } else {
      return Response.status(Response.Status.INTERNAL_SERVER_ERROR)
          .entity(
              ErrorPresenter.makeError(exception.getMessage(), "resolution", "endpoint", "method"))
          .build();
    }
  }
}

and in my RealmResourceProviderFactory I tried to register it:

public class MyCustomProviderFactory implements RealmResourceProviderFactory {

    @Override
    public void init(Config.Scope config) {
        // Any initialization code
    }

    @Override
    public void postInit(KeycloakSessionFactory factory) {
        ResteasyProviderFactory.getInstance().registerProvider(GlobalExceptionMapper.class);
    }
}

but this does absolutely nothing and everything else I found online does absolutely nothing. Any advice?