Cannot access DTO class in compiled JTE template when rendering dynamic templates from Database

[Jannaaa5]

I’m trying to render dynamic templates stored in a database using JTE in a Kotlin project. I’m using a setup similar to the examples in issue #451 and issue #170

I can successfully load and compile templates on-demand, but when a template references a Kotlin DTO or data class (e.g., DonationEmail), I get a ClassNotFoundException or similar errors. It seems the compiled template cannot find the class from my project when running in a self-contained jar.

Steps to reproduce:

1. Store a template in the database referencing a Kotlin DTO, e.g.:

  @param  com.example.demo.dto.DonationEmailDto donation
  <p>Hello ${donation.name}</p>

2. Load the template dynamically using DatabaseCodeResolver or a similar setup.
3. Render it with a DTO instance:

templateEngine.render(templateName, DonationEmail("John"), output)

4. Observe the class not found error.

Expected behavior:
The dynamic template should render correctly using the provided Kotlin DTO without errors.

Environment:

• JTE version: 3.2.1
• Kotlin version: 2.2.20
• JDK: 21
• Running as: self-contained fat jar / Spring Boot application

Question:
Is there a recommended way to make dynamic templates compiled at runtime recognize Kotlin DTO classes when running from a self-contained jar?

[edward3h]

Which class is not found? Can you share the stack trace?

[casid]

The stack trace would be very helpful.

Do you initialize the TemplateEngine with the Spring Boot classloader?

#280