Doubt middle table Hibernate ManyToMany

It's not impossible, no.

You have to create an intermediate entity that will represent the table in which, in your physical model, you will flatten that M: N relation and in which you will have the specific attributes of that relation and you will convert the M: N into two 1: N .

This is an example of me: I have an M: N relationship between the SeriesEdition entity and the EventSession entity. The detail is that for given an instance of championship (SeriesEdition), a session (EventSession) and a scoring system (PointsSystem), I need to save what multiplier points must be applied in that case (column ps_multiplier )

@Entity
@Table(name = "POINTS_SYSTEM_SESSION")
public class PointsSystemSession {

    @EmbeddedId
    private PointsSystemSessionPK id;

    @ManyToOne
    @MapsId("series_edition_id")
    @JoinColumn(name = "SERIES_EDITION_ID")
    private SeriesEdition seriesEdition;

    @ManyToOne
    @MapsId("session_id")
    @JoinColumn(name = "SESSION_ID")
    private EventSession eventSession;

    @ManyToOne
    private PointsSystem pointsSystem;

    @Column(name="ps_multiplier")
    private Float psMultiplier = 1.0f;

...
}

And just in case, although it does not necessarily have to be missing, this is the table that defines the key of the entity:

@Embeddable
public class PointsSystemSessionPK implements Serializable {

    private static final long serialVersionUID = -5431412749175457078L;

    @Column(name = "SESSION_ID")
    private Long sessionId;

    @Column(name = "SERIES_EDITION_ID")
    private Long seriesEditionId;

    public PointsSystemSessionPK() {
        super();
    }

    public PointsSystemSessionPK(Long sessionId, Long seriesEditionId) {
        this.sessionId = sessionId;
        this.seriesEditionId = seriesEditionId;
    }

...
}

I hope you find it useful