erro na repository.save(usuario);

Estou tendo esse erro repository.save e nao estou conseguindo descobrir o por que ` package br.com.alura.codechella.infra.gateways;

import br.com.alura.codechella.application.gateways.UserRepository; import br.com.alura.codechella.domain.entities.user.User; import br.com.alura.codechella.infra.persistence.UserEntity; import java.util.List;

public class JPAUserRepositories implements UserRepository {

private final UserRepository repository;
private final UserEntityMapper mapper;

public JPAUserRepositories(UserRepository repository, UserEntityMapper mapper) {
    this.repository = repository;
    this.mapper = mapper;
}


@Override
public User registerUser(User usuario) {
    UserEntity entity = mapper.toEntity(usuario);
    repository.save(usuario);
    return mapper.toDomain(entity);

}

@Override
public List<User> listAll() {

// return List.of(); return null; } } `

package br.com.alura.codechella.application.gateways;

import br.com.alura.codechella.domain.entities.user.User;
import br.com.alura.codechella.infra.persistence.UserEntity;

import java.util.List;

public interface UserRepository {
    User registerUser(User usuario);

    List<User> listAll();
}