No serializer found for class org.hibernate.proxy.pojo.javassist.Javassist?

Just to add this in, I ran into this same issue, but the supplied answers did not work. I fixed it by taking the exception's suggestion and adding to the application.properties file...

spring.jackson.serialization.fail-on-empty-beans=false

I'm using Spring Boot v1.3 with Hibernate 4.3

It now serializes the entire object and nested objects.

EDIT: 2018

Since this still gets comments I'll clarify here. This absolutely only hides the error. The performance implications are there. At the time, I needed something to deliver and work on it later (which I did via not using spring anymore). So yes, listen to someone else if you really want to solve the issue. If you just want it gone for now go ahead and use this answer. It's a terrible idea, but heck, might work for you. For the record, never had a crash or issue again after this. But it is probably the source of what ended up being a SQL performance nightmare.

I had a similar problem with lazy loading via the hibernate proxy object. Got around it by annotating the class having lazy loaded private properties with:

@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})

I assume you can add the properties on your proxy object that breaks the JSON serialization to that annotation.

The problem is that entities are loaded lazily and serialization happens before they get loaded fully.

Hibernate.initialize(<your getter method>);