Logging Entities in Spring with Lombok

Effectively use Lombok for logging while cautiously managing entities with lazy-loaded relationships to circumvent potential performance issues.

import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
import javax.persistence.*;
import java.util.Set;

@ToString(exclude = "orders") // Exclude lazy-loaded fields from toString
public class User {
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private String email;

    @OneToMany(mappedBy = "user", fetch = FetchType.LAZY)
    private Set<Order> orders; // Lazy-loaded relationship

Service Class with Lombok Logging:

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

public class UserService {

    public void updateUser(User user) {
        // Safe logging without initializing lazy-loaded 'orders'
        log.info("Updating user: {}", user);

Log Output Example:

Updating user: User(id=1, name=John Doe, email=john.doe@example.com)


Utilizing Lombok's @ToString annotation with the exclude attribute allows for the exclusion of lazy-loaded fields, such as orders in a User entity, preventing unintended loading during logging. The @Slf4j annotation simplifies logging setup, enabling efficient and safe logging practices in Spring applications. This approach ensures that entity logging is both informative and performance-conscious.

Detailed Explanation:

Before Lombok Integration:

Traditionally, logging entity information and managing lazy-loaded relationships required manually writing boilerplate code for logging setup and toString() methods, carefully avoiding lazy-loaded fields to prevent performance issues.

After Lombok Integration:

  • Simplified Logging: The @Slf4j annotation automatically injects a logger, reducing the boilerplate code for logger initialization.

  • Safe toString() Implementation: The @ToString(exclude = "orders") annotation generates a toString() method that excludes specified lazy-loaded fields, mitigating the risk of accidentally triggering database queries for uninitialized data.

Benefits of This Approach:

  • Performance Optimization: By excluding lazy-loaded fields from the toString() method, applications avoid unnecessary database hits and potential LazyInitializationException errors outside of transactional contexts.

  • Enhanced Maintainability: Reducing boilerplate code for logging and toString() methods makes the codebase cleaner and easier to maintain.

  • Improved Developer Productivity: Developers can focus on business logic rather than worrying about logging setup and the intricacies of lazy loading with Hibernate.


Lombok provides powerful annotations like @Slf4j and @ToString that simplify logging and toString implementations in Spring applications. When working with Hibernate entities, especially those with lazy-loaded relationships, Lombok's features help maintain performance and prevent common issues associated with lazy loading. This approach allows developers to enjoy the benefits of concise code and efficient logging while ensuring application performance remains optimal.

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