Payment entity before model updates

Payment.java

@Entity
public class Payment extends ManagedEntity implements IManagedEntity
{
    @Attribute
    @Identifier
    protected long paymentId;

    @Relationship(type = RelationshipType.ONE_TO_ONE,
            inverse = "payments",
            inverseClass = Invoice.class)
    protected Invoice invoice;

    @Index
    @Attribute
    protected double amount;

    @Attribute
    protected String notes;
}