Creacion de una clase para una relacion M:M con el id embebido. Observar como queda el repositorio.

CourseEnrollment.java

@Entity
public class CourseEnrollment {

    @EmbeddedId
    protected Id id = new Id();

    @ManyToOne(optional = false, fetch = FetchType.LAZY)
    @JoinColumn(name = "student_id", insertable = false, updatable = false)
    protected Student student;

    @ManyToOne(optional = false, fetch = FetchType.LAZY)
    @JoinColumn(name = "edition_id", insertable = false, updatable = false)
    protected CourseEdition edition;

    @Column(nullable = false)
    protected Boolean isDropped;

    @ManyToOne(fetch = FetchType.LAZY)
    protected Evaluation evaluation;

    public CourseEnrollment() {
    }

    public CourseEnrollment(Student student, CourseEdition edition) {
        this(student, edition, false, null);
    }

    public CourseEnrollment(Student student, CourseEdition edition, Boolean isDropped, Evaluation evaluation) {
        this.id.editionId = edition.getId();
        this.id.studentId = student.getId();
        this.student = student;
        this.edition = edition;
        this.isDropped = isDropped;
        this.evaluation = evaluation;

    }
    
    //getters and setters
    
    @Embeddable
    public static class Id implements Serializable {

        @Column(name = "student_id")
        protected Long studentId;

        @Column(name = "edition_id")
        protected Long editionId;

        public Id() {
        }

        public Id(Long studentId, Long editionId) {
            this.studentId = studentId;
            this.editionId = editionId;
        }

        public boolean equals(Object o) {
            if (o instanceof Id that) {
                return this.studentId.equals(that.studentId)
                        && this.editionId.equals(that.editionId);
            }
            return false;
        }

        public int hashCode() {
            return studentId.hashCode() + editionId.hashCode();
        }

    }

}

Repository.java

public interface CourseEnrollmentRepository extends JpaRepository<CourseEnrollment, CourseEnrollment.Id> {
}