Define Mapping relationship with JPA

I am having difficulties to figure out what's proper w开发者_StackOverflow社区ay of defining the following relationships with JPA2 mapping.

create table TableA {
  id int primary key
  name varchar(255) not null
);

create table TableB {
  x_id int not null REFERENCES TableA(id),
  y_id int not null REFERENCES TableA(id),
  PRIMARY KEY (x_id, y_id)
);

Since there is a composite key involved, I know I need to define a serializable class such as FooPK.

@Embeddable 
public class FooPK {
    @Column(name = "x_id", insertable=true, nullable=false)
    private long x_id;

    @Column(name = "y_id", insertable=true, nullable=false)
    private long y_id;
    ...
}

But I am lost on where to define @OneToMany and @ManyToOne relationship and how to properly write down the @JoinColumn() in this case.

Any help is much appreciated.

Oliver

Try to use @ManyToMany annotation.

You don't need to define the intermediate class.

More info: http://download.oracle.com/javaee/5/api/javax/persistence/ManyToMany.html