The RequestBean.createPart business method creates a new Part entity. The EntityManager.persist method is used to persist the newly created entity to the database.
Part part = new Part(partNumber, revision, description, revisionDate, specification, drawing); em.persist(part);
The ConfigBean singleton session bean is used to initialize the data in order. ConfigBean is annotated with @Startup, which indicates that the EJB container should create ConfigBean when order is deployed. The createData method is annotated with @PostConstruct, and it creates the initial entities used by order by calling RequestsBean's business methods.