No unique bean of type [javax.persistence.EntityManager] is defined

Answer 1

Your Spring context has a bean definition using LocalContainerEntityManagerFactoryBean. This creates an EntityManagerFactory, not an EntityManager.

AssignmentDao needs to get itself wired with an EntityManagerFactory.

Alternatively, you can replace the LocalContainerEntityManagerFactoryBean with a LocalEntityManagerFactoryBean, which will create an EntityManager directly. However, you need to be careful with that one, it has some downsides. See that part of the Spring docs for a full explanation of the options.

It's confusing, because the naming conventions of JPA and Spring overlap each other, so naming these classes is a real bugger.