JPA @OneToMany but with only one rekord

Question

I have a table in the database that has a @OneToMany link to another table, JPA in standard form will return me the values from the other table as a list, however I would like to get the records as:

SELECT * FROM a LEFT JOIN b ON b.a_id = a.id

so if there are 2 records in the table "b" then I should get a list of 2 elements, not a one element list with a list inside that has values from table "b". Additionally, I will point out that I care to implement this by the function "Page findAll(@Nullable Specification spec, Pageable pageable);". Example entity:

@Entity public class A {

 private Long id; @OneToMany private List<B> b;

soo i like to look like this

@Entity public class A {

 private Long id; @OneToOne private B b;

But when theres more that one B i will get second rekord instede of error.

What can I do to achieve this?