InvalidDefinitionException ☕ Java

com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class X and no properties discovered

Jackson can’t serialize the class — it has no public getters/fields, or it’s a Hibernate proxy, or Java 8 date types without the JSR-310 module.

Seen on: Java

Meaning

Common variants: “No serializer found … no properties discovered” (no getters), Hibernate lazy proxies (hibernateLazyInitializer), and “Java 8 date/time type not supported by default”.

Common causes

  • Class without public getters/fields
  • Serializing Hibernate lazy proxies
  • java.time types without jackson-datatype-jsr310

⚡ Quick fix

  1. Add getters or @JsonAutoDetect
  2. Return DTOs instead of entities
  3. Register JavaTimeModule

Detailed fix by platform

Java

  1. mapper.registerModule(new JavaTimeModule());

How to diagnose

  1. Class — Which class is named?
  2. Variant — Proxy, getters or date types?

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