I created a new Ninja application using the ninja-servlet-jpa-blog-archetype, version 7.0.0. When executing it on Java 18 or 21, I got the error below, which I could work around by declaring a newer version of Javassist in the application’s pom.xml:
org.hibernate.HibernateException: HHH000142: Javassist Enhancement failed: models.Article
<dependency>
<groupId>org.javassist</groupId>
<artifactId>javassist</artifactId>
<version>3.25.0-GA</version>
</dependency>