What is the Criteria API in Hibernate 7 and what are SelectionSpecification and RestrictionSpecification?

// Static metamodel auto-generated by hibernate-processor:
// public abstract class Product_ {
//     public static volatile SingularAttribute<Product, Long> id;
//     public static volatile SingularAttribute<Product, String> name;
//     public static volatile SingularAttribute<Product, BigDecimal> price;
// }

// Hibernate 7: NEW SelectionSpecification API
var results = SelectionSpecification
    .create(Product.class)
    .restrict(Restriction.equal(Product_.status, ProductStatus.ACTIVE))
    .restrict(Restriction.contains(Product_.name, "book", false))
    .restrict(Restriction.greaterThan(Product_.price, new BigDecimal("10")))
    .sort(Order.desc(Product_.price))
    .createQuery(session)
    .setMaxResults(20)
    .getResultList();

// RestrictionSpecification: add restrictions to an EXISTING query
var priceFilter = RestrictionSpecification
    .of(Product.class)
    .where(Restriction.between(Product_.price, new BigDecimal("10"), new BigDecimal("100")));

var update = session.createMutationQuery("UPDATE Product SET discount = :disc");
priceFilter.applyTo(update);
update.setParameter("disc", new BigDecimal("5")).executeUpdate();

// Traditional JPA Criteria still works:
CriteriaBuilder cb = session.getCriteriaBuilder();
CriteriaQuery<Product> cq = cb.createQuery(Product.class);
Root<Product> root = cq.from(Product.class);
cq.where(cb.equal(root.get(Product_.status), ProductStatus.ACTIVE));
List<Product> r = session.createQuery(cq).getResultList();