In the process of #36270, it turns out that neither Hibernate nor EclipseLink detect the standard "jakarta.persistence.dataSource" property as expected - whereas they do detect a DataSource instance given to the "jakarta.persistence.nonJtaDataSource" property, despite that property only being defined for a JNDI name String. Exposing both properties works fine against Hibernate as well as EclipseLink, so we can fix LocalEntityManagerFactoryBean#setDataSource along those lines.