How do I disable fail_on_empty_beans in Jackson?

java

objectmapper

jackson-configuration

spring-boot

byAlex Kataev·Feb 12, 2025

To disable Jackson's fail_on_empty_beans, configure your ObjectMapper:

new ObjectMapper().disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);

Like a charm, prevents serialization hiccups with empty Java objects.

In case you prefer a class-level configuration instead of a macro solution:

@JsonSerialize(using = ObjectMapper.DefaultSerializer.class)
public class YourClass {
    // Your class content - *because your class is never empty*, right? 😉
}

Global configuration in Spring Boot

Working with Spring Boot? Add this to application.properties:

spring.jackson.serialization.FAIL_ON_EMPTY_BEANS=false

This little entry says "Not today, serialization exceptions!" across the entire Spring Boot ecosystem.

Just ignore it — Selectively!

Perhaps, you only want to ignore certain properties during serialization. Use @JsonIgnoreProperties:

@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class YourEntity {
    // Your fields and methods - *marshal at will!* 🚓
}

Including hibernateLazyInitializer and handler in the ignore list is like a secret trick that prestige magicians don't reveal (especially useful when dealing with JPA and Hibernate).

DTOs — Keep it clean

For situations needing an API as clean as a whistle, transform entities into Data Transfer Objects (DTOs) before serialization. Not only you dodge the fail_on_empty_beans issue like Neo from the Matrix, but you also gain better control over the data structure. Now that's grace under pressure!

Tackling advanced configurations

Got a more sophisticated project setup pushing the envelope? Explore the deep ends of Jackson and Spring Boot documentation. Trust me, they're a goldmine when it comes to handling REST APIs with Jersey, or other scenarios you might run into.

Deciphering error messages

When you face the fail_on_empty_beans error, don't just pull your hair out. The error message often holds the key to the bean or property causing trouble. Use this information to fine-tune your ObjectMapper or adjust your class definition. Like reading tea leaves, only more technical!

The public methods gotcha

In the Jackson world, public methods are seen as potential getters. Having these without corresponding field data is like starting a water gun fight with an empty gun — bound to lead to fail_on_empty_beans. So, suit up your methods with appropriate data or mark them to be ignored by Jackson.

explain-codes / Java / How do I disable fail_on_empty_beans in Jackson?

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Global configuration in Spring Boot Just ignore it — Selectively!DTOs — Keep it clean Tackling advanced configurations Deciphering error messages The public methods gotcha