Loading data fails with "Specified class is an interface" when invoking repository from worker thread

[cstettler]

Loading data having a property using a type discriminator from a worker thread (i.e. from a rest controller in a parallel stream) sometimes results in the following error:

org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.foo.Bar]: Specified class is an interface

The following aspects seem to be relevant in order to run into this issue:

• the entity must contain a field of an interface type that contains several concrete implementations as values
• the entity has to be loaded from a separate thread other than the http handler thread (e.g. from a worker thread of the common pool)
• the application has to be run from the Spring Boot jar (e.g. from command line or a Docker image), not from the IDE

Please see https://github.com/cstettler/spring-data-mongo-loading-issue for a minimal sample application based on Spring Boot 2.6.1 and Spring Data Mongo 3.3.0 to reproduce the issue and further explanation / results of the investigation done so far.

Note: I am aware that this issue might not be caused by Spring Data MongoDB directly, but by Spring Data or even by Spring Boot. Please advice in case the issue should be opened in a different Spring project repository. Thank you!

[mp911de]

This is a duplicate of #3905. Please make sure to either use type aliases or set the class loader accordingly. ForkJoin thread pools use the system class loader and not Spring's class loader.