HSQL default identity 0 conflicts with jpa entities with identity int id defaulted to 0

I have a JPA entity with:

@Id
@Column(name = "id", columnDefinition = "INT")
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;

and using EntityManager.merge by default

For testing I'm using HSQL that default its "auto increment" setting to 0

whenever I create a new object, my default int id will be set to 0, and the merge operation, instead of inserting the object as a new record, will update it instead.

any idea how to solve this?

One option I tried without success is to set the default "auto increment" of HSQL to 1 (not altering a specific column using RESTART)

thanks!