User:


@Entity
@Table(name = "user")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private int id;

    @Column(name = "user_name")
    private String userName;

    @Column(name = "password")
    private String password;

    @Column(name = "active")
    private boolean active;

    @Column(name = "roles")
    private String roles;
}

Match:

@Entity
@Table(name = "match")
public class Match {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "match_id")
    private int matchId;

    @OneToOne
    private User firstPerson;

    @OneToOne
    private User secondPerson;

    @OneToMany(mappedBy = "match")
    private Set<MatchSet> matchSet;
}

MatchSet:

@Entity
@Table(name = "match_set")
public class MatchSet {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private int id;

    @Column(name = "firstPerson")
    private int firstPerson;

    @Column(name = "secondPerson")
    private int secondPerson;

    @ManyToOne
    @JoinColumn(name = "match_id")
    private Match match;

}