@Document(indexName = "company")
@Data
@Builder
public class Company {
  @Id
  private String id;

  @Field(type = FieldType.Keyword)
  private String name;

  @Field(type = FieldType.Text)
  private String address;

  private GenericField<String> relation;
}

public class GenericField<T> {

  private T parent;
  private String name;

  public T getParent() {
    return parent;
  }

  public void setParent(T parent) {
    this.parent = parent;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (!(o instanceof GenericField<?> that)) return false;
    return Objects.equals(parent, that.parent) && Objects.equals(name, that.name);
  }

  @Override
  public int hashCode() {
    return Objects.hash(parent, name);
  }
}

@Repository
public interface CompanyRepository extends ReactiveCrudRepository<Company, String> {
}

    Iterator<PersistentEntity<?, ? extends PersistentProperty<?>>> entities = persistentEntities.iterator();
    while(entities.hasNext()) {
      PersistentEntity<?, ? extends PersistentProperty<?>> entity = entities.next();
      TypeInformation<?> typeInformation = entity.getTypeInformation();
      Class entityClass = entity.getType();
      ......
    }