@ColumnTransformer(read = "decrypt(credit_card_num, 'my_secret_key')")
private String creditCardNumber;

@ColumnTransformer(write = "encrypt(?, 'my_secret_key')")
private String password;

SELECT decrypt(credit_card_num, 'my_secret_key') FROM users WHERE id = 1;

INSERT INTO users (password) VALUES (encrypt('qwerty', 'my_secret_key'));

@Entity
public class User {
    @Id 
    private Long id;

    @ColumnTransformer(
        read = "pgp_sym_decrypt(credit_card_num, 'secret_key')",
        write = "pgp_sym_encrypt(?, 'secret_key')"
    )
    @Column(name = "credit_card_num")
    private String creditCardNumber;
}

@ColumnTransformer(
    read = "CAST(price AS decimal(10,2))",
    write = "CAST(? AS varchar)"
)
private BigDecimal price;

@ColumnTransformer(
    read = "COALESCE(status, 'DEFAULT')"
)
private String status;

import java.util.function.Supplier;

public class Task080425 {
    public static void main(String[] args) {
        int x = 5;
        Supplier<Integer> lambda = () -> x + 1;
        x = 10;
        System.out.println(lambda.get());
    }
}

@Entity
@DynamicInsert
public class User { ... }

User user = new User();
user.setId(1L);
user.setName("Alice"); // age = null

INSERT INTO user (id, name, age) VALUES (1, 'Alice', NULL);

@DynamicInsert
@Entity
public class User { ... }

INSERT INTO user (id, name) VALUES (1, 'Alice');  -- поле age пропущено!

hibernate.dynamic_insert=true  # Применяется ко всем сущностям!

@DynamicInsert
@Entity
public class Product {
    @Id 
    private Long id;
    private String name;
    private Integer stock;  // Часто null для новых товаров
}

INSERT INTO product (id, name) VALUES (1, 'Laptop');

@DynamicInsert
@Entity
public class Account {
    @Id 
    private Long id;

    @ColumnDefault("0")
    private BigDecimal balance;  // Если null, БД подставит 0
}

@Entity
@DynamicUpdate
public class User { ... }

User user = session.get(User.class, 1L);
user.setName("Alice"); // Меняем только имя

UPDATE user SET name='Alice', age=30, email='alice@example.com' WHERE id=1;

@DynamicUpdate
@Entity
public class User { ... }

UPDATE user SET name='Alice' WHERE id=1;  -- Только измененное поле!

hibernate.dynamic_update=true  # Применяется ко всем сущностям

import java.util.HashSet;
import java.util.Set;

public class Task090425 {
    public static void main(String[] args) {
        Set<String> set = new HashSet<>();
        set.add("A");
        set.add(new String("A"));
        set.add("B");
        set.remove(new String("A"));
        
        System.out.println(set.size());
    }
}

@Entity
@FilterDef(name = "activeUserFilter", 
           condition = "is_active = :activeStatus", 
           parameters = @ParamDef(name = "activeStatus", type = boolean.class))
@Filter(name = "activeUserFilter")
public class User { ... }

session.enableFilter("activeUserFilter")
       .setParameter("activeStatus", true);

session.disableFilter("activeUserFilter");

@Repository
public class UserRepository {
    @PersistenceContext
    private EntityManager em;

    public List<User> findActiveUsers() {
        em.unwrap(Session.class)
          .enableFilter("activeUserFilter")
          .setParameter("activeStatus", true);
        return em.createQuery("FROM User", User.class).getResultList();
    }
}

@Component
public class HibernateFilterConfig {
    @PersistenceContext
    private EntityManager em;

    @PostConstruct
    public void init() {
        Session session = em.unwrap(Session.class);
        session.enableFilter("activeUserFilter")
               .setParameter("activeStatus", true);
    }
}

@Entity
public class Department {
    @OneToMany(mappedBy = "department")
    @Filter(name = "activeUserFilter", condition = "is_active = :activeStatus")
    private List<User> users;
}

@Entity
@FilterDef(name = "activeFilter", condition = "is_active = :active")
@FilterDef(name = "roleFilter", condition = "role = :roleName")
@Filter(name = "activeFilter")
@Filter(name = "roleFilter")
public class User { ... }

// Включение разных параметров в runtime
session.enableFilter("activeUserFilter")
       .setParameter("activeStatus", true);
session.enableFilter("roleFilter")
       .setParameter("roleName", "ADMIN");

@Formula("(SELECT COUNT(*) FROM orders o WHERE o.customer_id = id)")
private int orderCount;

@Formula("CONCAT(first_name, ' ', last_name)")
private String fullName;
Для MySQL CONCAT работает аналогично, но в Oracle нужно использовать ||.

@Formula("(SELECT AVG(r.rating) FROM reviews r WHERE r.product_id = id)")
private Double averageRating;

@Formula("TO_CHAR(created_at, 'YYYY-MM-DD')")
private String creationDate;

@Transient
private int orderCount;

@PostLoad
private void calculateOrderCount() {
    this.orderCount = orderRepository.countByCustomerId(this.id);
}

import java.util.HashSet;
import java.util.Set;

class Person1004 {
    String name;

    Person1004(String name) { this.name = name; }

    public boolean equals(Object o) {
        return this.name.length() == ((Person1004)o).name.length();
    }
}

public class Task100425 {
    public static void main(String[] args) {
        Set<Person1004> set = new HashSet<>();
        set.add(new Person1004("Alice"));
        set.add(new Person1004("Bob"));
        set.add(new Person1004("Charlie"));
        set.add(new Person1004("Dave"));

        System.out.println(set.size());
    }
}