JPA: Override Auto generated ID

I have following definition in Employee class

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "employee_id")
private Integer employeeId;

Now I want to import existing employees with existing employee IDs. Even if I set the employee ID before saving, the assigned ID is ignored and auto incremented ID is stored. How do we override this?

I had similar problem for composite key which has been explained here