[FIXED] LazyInitializationException in a Spring Transaction

Issue

In a Spring Boot project I am working at I added the Hibernate ORM plugin to enable lazy loading for @Lob fields in my entity, this didn't work out of the box for DB2. The lazy loading works, when I retrieve the object the lob field isn't loaded yet. But now a new problem occurs, when I do want to get the blob field I get a LazyInitializationException. Now I did some debugging and Google searches. I tried to add @Transactional to the method and to the classes, I also tried multiple propagation options, but nothing works.

I also tried to load the object directly using the EntityManager, but that also gives the same exception:

Object object = entityManager.find(Object.class, id);
object.getLobField();

The full exception that is thrown is:

org.hibernate.LazyInitializationException: Unable to perform requested lazy initialization [package.Object.lobField] - no session and settings disallow loading outside the Session

Solution

You need to activate in your application.yml

spring:
  jpa:
    properties:
      hibernate:
        enable_lazy_load_no_trans: true

This will allow lazy loading to work outside the session that created the object that has properties that are lazy loaded.

Reference: https://www.baeldung.com/hibernate-lazy-loading-workaround, Solve Hibernate Lazy-Init issue with hibernate.enable_lazy_load_no_trans and https://vladmihalcea.com/the-hibernate-enable_lazy_load_no_trans-anti-pattern/

Answered By - pringi
Answer Checked By - David Goodson (JavaFixing Volunteer)