Manytoone mapping for two tables to the single entity - spring-boot

Question

Class A{
private int campid;
private string name;
}
Class B {
Private int campid;
Private string name;
}`
Class combo{
private int id;
private string phonenumber;
}
I'm trying like this
Class A{
private int campid;
private string name;
#OneToMany(targetEntity = Combo.class,mappedBy ="a",fetch = FetchType.LAZY,cascade=CascadeType.ALL )
private Combo combo;
}
Class B {
Private int campid;
Private string name;
#OneToMany(targetEntity = Combo.class,mappedBy ="b",fetch = FetchType.LAZY,cascade=CascadeType.ALL )
private Combo combo;
}`
Class combo{
private int id;
private string phonenumber;
#ManyToOne
#JoinColumn(name = "Camp_Id_fk",insertable=true, updatable=true)
private A a;
#ManyToOne
#JoinColumn(name = "Camp_Id_fk",insertable=true, updatable=true)
private B b;
}
want to store the campid of class A and campid class B as the foreign key in the combo table. One campid can have multiple phone numbers.
I want to do this in spring jpa..I'm not understanding how to do it

Answer 1

#Entity
#Table(name = "a")
public class A {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "camp_id")
private Long campid;
#Column(name = "name")
private String name;
#Column
#ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.MERGE)
#JoinTable(name = "a_combo",
joinColumns = #JoinColumn(name = "camp _id"),
inverseJoinColumns = #JoinColumn(name = "id"))
private Set<Combo> comboSet = new HashSet<>();
}
And same for B class