Spring Data JPA 3.5でSpecification.whereが非推奨になった件

/**
 * Simple static factory method to add some syntactic sugar around a {@link Specification}.
 *
 * @apiNote with 4.0, this method will no longer accept {@literal null} specifications.
 * @param <T> the type of the {@link Root} the resulting {@literal Specification} operates on.
 * @param spec can be {@literal null}.
 * @return guaranteed to be not {@literal null}.
 * @since 2.0
 * @deprecated since 3.5, to be removed with 4.0 as we no longer want to support {@literal null} specifications.
 */
@Deprecated(since = "3.5.0", forRemoval = true)
static <T> Specification<T> where(@Nullable Specification<T> spec) {
    return spec == null ? (root, query, builder) -> null : spec;
}

/**
 * Simple static factory method to add some syntactic sugar translating {@link PredicateSpecification} to
 * {@link Specification}.
 *
 * @param <T> the type of the {@link Root} the resulting {@literal Specification} operates on.
 * @param spec the {@link PredicateSpecification} to wrap.
 * @return guaranteed to be not {@literal null}.
 */
static <T> Specification<T> where(PredicateSpecification<T> spec) {

    Assert.notNull(spec, "PredicateSpecification must not be null");

    return (root, update, criteriaBuilder) -> spec.toPredicate(root, criteriaBuilder);
}