An application that has been working well for months has stopped picking up the JPA `@Entity` annotations that have been a part of it for months. As my integration tests run I see dozens of "`org.hibernate.MappingException: Unknown entity: com.whatever.OrderSystem`" type errors.

It isn't clear to me what's gone wrong here.

I have no `hibernate.cfg.xml` file because I'm using the Hibernate Entity Manager. Since I'm exclusively using annotations, there are no .hbm.xml files for my entities. My `persistence.xml` file is minimal, and lives in `META-INF` as it is supposed to.

I'm obviously missing something but can't put my finger on it.

I'm using hibernate-annotations 3.2.1, hibernate-entitymanager 3.2.1, persistence-api 1.0 and hibernate 3.2.1. hibernate-commons-annotations is also a part of the project's POM but I don't know if that's relevant.

Is there a web.xml entry that has vanished, or a Spring configuration entry that has accidentally been deleted?