@Entity
@EntityListeners(AuditingEntityListener.class)
public class Document {
    @CreatedBy
    private String createdBy;

    // Другие поля
}

@Configuration
@EnableJpaAuditing
public class AuditConfig {
    @Bean
    public AuditorAware<String> auditorProvider() {
        return () -> Optional.ofNullable(SecurityContextHolder.getContext())
                            .map(SecurityContext::getAuthentication)
                            .map(Authentication::getName);
    }
}

@Entity
@EntityListeners(AuditingEntityListener.class)
public class Order {
    @CreatedBy
    private String createdBy;
    
    @CreatedDate
    private LocalDateTime createdDate;
    
    // Другие поля
}

spring.security.user.name=admin
spring.security.user.password=secret

public class SecurityAuditorAware implements AuditorAware<String> {
    @Override
    public Optional<String> getCurrentAuditor() {
        return Optional.ofNullable(SecurityContextHolder.getContext())
                      .map(SecurityContext::getAuthentication)
                      .filter(Authentication::isAuthenticated)
                      .map(Authentication::getName);
    }
}

@CreatedBy
private String createdBy;

@CreatedDate
private LocalDateTime createdDate;

@LastModifiedBy
private String lastModifiedBy;

@LastModifiedDate
private LocalDateTime lastModifiedDate;

import java.util.LinkedList;

public class Task310325 {
    public static void main(String[] args) {
        LinkedList<Integer> list = new LinkedList<>();
        list.add(1);
        list.add(2);
        list.addFirst(3);
        list.removeLast();
        
        System.out.println(list.get(1));
    }
}

@Entity
@EntityListeners(AuditingEntityListener.class)
public class Document {
    @CreatedDate
    private LocalDateTime createdAt;
    
    // Другие поля
}

@Configuration
@EnableJpaAuditing
public class AuditConfig {
    // Дополнительные настройки при необходимости
}

@Entity
@EntityListeners(AuditingEntityListener.class)
public class Order {
    @CreatedDate
    private LocalDateTime createdAt;
    
    @LastModifiedDate
    private LocalDateTime updatedAt;
    
    // Другие поля
}

spring.jpa.properties.hibernate.jdbc.time_zone=UTC

@CreatedDate
private LocalDateTime createdAt;

@CreatedBy
private String createdBy;

@LastModifiedDate
private LocalDateTime updatedAt;

@LastModifiedBy
private String updatedBy;

@CreatedDate
private Date createdAt;  // java.util.Date

@CreatedDate
private Long createdTimestamp;  // timestamp в миллисекундах

@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
@CreatedDate
private LocalDateTime createdAt;

public interface OrderProjection {
    @Value("#{target.createdAt}")
    String getFormattedCreatedAt();
}

@Entity
@EntityListeners(AuditingEntityListener.class)
public class Document {
    @LastModifiedBy
    private String lastModifiedBy;
    
    // Другие поля
}

@Entity
@EntityListeners(AuditingEntityListener.class)
public class Document {
    @LastModifiedDate
    private LocalDateTime lastModifiedAt;
    
    // Другие поля
}

@Entity
@EntityListeners(AuditingEntityListener.class)
public class Product {
    @Id
    private Long id;
    
    @CreatedBy
    private String createdBy;
    
    @CreatedDate
    private LocalDateTime createdAt;
    
    @LastModifiedBy
    private String lastModifiedBy;
    
    @LastModifiedDate
    private LocalDateTime lastModifiedAt;
    
    // Бизнес-поля
    private String name;
    private BigDecimal price;
}

product.setPrice(new BigDecimal("99.99"));
productRepository.save(product);
Поля lastModifiedBy/At будут автоматически обновлены
Поля createdBy/At останутся без изменений

@SpringBootApplication
@EnableJpaAuditing
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

@Bean
public AuditorAware<String> auditorAware() {
    return () -> Optional.ofNullable(SecurityContextHolder.getContext())
                        .map(SecurityContext::getAuthentication)
                        .filter(Authentication::isAuthenticated)
                        .map(Authentication::getName);
}

spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

spring.jackson.date-format=yyyy-MM-dd HH:mm:ss
spring.jackson.time-zone=UTC

@Query("SELECT p FROM Product p WHERE p.lastModifiedAt > :since")
List<Product> findRecentlyModified(@Param("since") LocalDateTime since);

public class Task010425 {
    public static void main(String[] args) {
        double x = -2.5;
        double result = Math.abs(Math.floor(x));
        System.out.println(result);
    }
}

@Entity
public class Product {
    @Id
    private Long id;
    
    @Version
    private Integer version;
    
    // другие поля
}

Product product = em.find(Product.class, 1L);
// product.version = 1 (текущее значение в БД)

product.setPrice(newPrice);
em.merge(product);

UPDATE product 
SET ..., version = version + 1 
WHERE id = 1 AND version = 1

@ExceptionHandler(OptimisticLockException.class)
public ResponseEntity<String> handleConflict(OptimisticLockException ex) {
    return ResponseEntity.status(HttpStatus.CONFLICT).body("Объект был изменен другим пользователем");
}

@Service
@Transactional
public class ProductService {
    public void updatePrice(Long id, BigDecimal newPrice) {
        Product product = productRepository.findById(id).orElseThrow();
        product.setPrice(newPrice);
        // При коммите транзакции версия автоматически увеличится
    }
}

public void updateWithVersionCheck(Long id, Integer expectedVersion, Product update) {
    Product product = productRepository.findById(id).orElseThrow();
    if (!product.getVersion().equals(expectedVersion)) {
        throw new OptimisticLockException("Версия не совпадает");
    }
    // ... обновление
}

public class ProductDto {
    private Long id;
    private Integer version;
    // другие поля
    
    public Product toEntity() {
        Product product = new Product();
        product.setId(this.id);
        product.setVersion(this.version);
        // ...
        return product;
    }
}

@Lock(LockModeType.PESSIMISTIC_WRITE)
Product findByIdForUpdate(Long id);

@PersistenceContext(name = "myPersistenceUnit")
private EntityManager entityManager;

@PersistenceContext(unitName = "myPersistenceUnit")
private EntityManager entityManager;

@PersistenceContext(type = PersistenceContextType.EXTENDED)
private EntityManager entityManager;

@PersistenceContext(properties = {
    @PersistenceProperty(name = "hibernate.jdbc.batch_size", value = "20")
})
private EntityManager entityManager;

@Bean
@Primary
public LocalContainerEntityManagerFactoryBean entityManagerFactory(DataSource dataSource) {
    LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
    em.setDataSource(dataSource);
    em.setPackagesToScan("com.example.domain");
    em.setJpaVendorAdapter(new HibernateJpaVendorAdapter());
    return em;
}

@PersistenceUnit
private EntityManagerFactory emf;

public void someMethod() {
    EntityManager em = emf.createEntityManager();
    try {
        em.getTransaction().begin();
        // ... операции с БД ...
        em.getTransaction().commit();
    } finally {
        em.close();
    }
}