I experimented with EclipseLink JPA and basic operations worked fine for me. JPA is a Java standard and there are other implementations that may also work (OpenJPA, etc). Here is an example of what a JPA class in Scala looks like:
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
@Entity { val name = "Users" }
class User {
@Id
@GeneratedValue
var userid:Long = _
var login:String = _
var password:String = _
var firstName:String = _
var lastName:String = _
}