We are migrating from Spring 2.x.x(Hibernate 5) to Spring 3.x.x (Hibernate 6). Test case we using H2. But getting unique key constraint issue

Entity class

@Getter
@Setter
@NoArgsConstructor
@Entity
@ToString
@Table(name = "category_config")
public class CategoryConfig extends BaseEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @NotNull(groups = Existing.class)
    @Null(groups = New.class)
    private Long categoryConfigId;

Service class

public CategoryConfig addCategory(CategoryConfig

categoryConfig,String tenantId) {
    log.info(" info categoryConfig {} ", categoryConfig);
    if (categoryConfig == null||categoryConfig.getDeptNbr()==null) {
        throw new AllocationRuntimeException(ErrorCodes.CATEGORY_NUMBER_MANDATORY.getError());
    }
    categoryConfig.setTenantId(tenantId);
    categoryConfig.setAllocationStatus(ItemSetupAllocationStatus.PROGRESS.getValue());
    categoryConfig.setItemType(ItemType.INSEASON.getValue());
    try {
        return categoryConfigRepository.save(categoryConfig);
    } catch (Exception e) {
        throw new AllocationRuntimeException(e,
                ErrorCodes.CATEGORY_NUMBER_ALREADY_CONFIGURED.getError(categoryConfig.getDeptNbr()));
    }
}

h2 config:

spring:
    cloud:
        gcp:
          core:
            enabled: false
          bigquery:
            datasetName: test
            project-id: test
            enabled: false
        azure:
           storage:
              blob:
                storage-url: https://test.blob.core.windows.net
    datasource:
        driver-class-name: org.h2.Driver
        url: jdbc:h2:mem:testdb;DB_CLOSE_ON_EXIT=FALSE
        username:
        password:
    jpa:
        defer-datasource-initialization: true
        database-platform: org.hibernate.dialect.H2Dialect
        show-sql: true
        properties:
            hibernate:
                format_sql: true
                ddl-auto: update

Data inside h2:

INSERT INTO category_config(category_config_id, dept_nbr, dept_desc, created_by, created_on, last_updated_by, last_updated_on, sum_need_qty_cdf, sum_need_qty_legacy, allocated_items, wk_supply, wk_supply_legacy, allocation_description, inherit_global_decile, isVLTRequired, tenant_id, allocation_status, item_type, current_doh) VALUES(1, 202, 'edit cat test', 's0k06wm', '2022-08-26', 's0k06wm', '2022-08-26', NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 'sams_us', 'Allocation available', 'inseason,preseason',7)
INSERT INTO category_config(category_config_id, dept_nbr, dept_desc, created_by, created_on, last_updated_by, last_updated_on, sum_need_qty_cdf, sum_need_qty_legacy, allocated_items, wk_supply, wk_supply_legacy, allocation_description, inherit_global_decile, isVLTRequired, tenant_id, allocation_status, item_type, current_doh) VALUES(2, 12, 'cat test 12', 's0k06wm', '2022-08-26', 's0k06wm', '2022-08-26', NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 'sams_mx', 'Allocation available', 'inseason',8)
INSERT INTO category_config(category_config_id, dept_nbr, dept_desc, created_by, created_on, last_updated_by, last_updated_on, sum_need_qty_cdf, sum_need_qty_legacy, allocated_items, wk_supply, wk_supply_legacy, allocation_description, inherit_global_decile, isVLTRequired, tenant_id, allocation_status, item_type, current_doh) VALUES(3, 14, 'cat test 14', 's0k06wm', '2022-08-26', 's0k06wm', '2022-08-26', NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 'sams_mx', 'Allocation available', 'inseason,preseason',8)
INSERT INTO category_config(category_config_id, dept_nbr, dept_desc, created_by, created_on, last_updated_by, last_updated_on, sum_need_qty_cdf, sum_need_qty_legacy, allocated_items, wk_supply, wk_supply_legacy, allocation_description, inherit_global_decile, isVLTRequired, tenant_id, allocation_status, item_type, current_doh) VALUES(4, 7, 'JUGUETES', 's0k06wm', '2022-08-26', 's0k06wm', '2022-08-26', NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 'sams_mx', 'Allocation available', 'inseason,preseason',8)
INSERT INTO category_config(category_config_id, dept_nbr, dept_desc, created_by, created_on, last_updated_by, last_updated_on, sum_need_qty_cdf, sum_need_qty_legacy, allocated_items, wk_supply, wk_supply_legacy, allocation_description, inherit_global_decile, isVLTRequired, tenant_id, allocation_status, item_type, current_doh) VALUES(5, 1990, 'edit cat test', 's0r0e4g', '2023-05-30', 's0r0e4g', '2023-05-30', NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 'sams_us', 'Allocation available', 'inseason',8)
INSERT INTO category_config(category_config_id, dept_nbr, dept_desc, created_by, created_on, last_updated_by, last_updated_on, sum_need_qty_cdf, sum_need_qty_legacy, allocated_items, wk_supply, wk_supply_legacy, allocation_description, inherit_global_decile, isVLTRequired, tenant_id, allocation_status, item_type, current_doh) VALUES(6, 5000, 'test cat', 's0k06wm', '2022-08-26', 's0k06wm', '2022-08-26', NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 'sams_mx', 'Allocation available', 'inseason,preseason',8)

It was working fine in Spring 2.x.x. But in Spring 3.x.x. Im getting

could not execute statement [Unique index or primary key violation: "PRIMARY KEY ON PUBLIC.CATEGORY_CONFIG(CATEGORY_CONFIG_ID) ( /* key:1 */ NULL, 7, NULL, 202, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, CAST(1 AS BIGINT), TIMESTAMP '2022-08-26 00:00:00', TIMESTAMP '2022-08-26 00:00:00', NULL, 'Allocation available', 's0k06wm', 'edit cat test', 'inseason,preseason', 's0k06wm', 'sams_us')"; SQL statement:
insert into category_config (allocated_items,allocation_description,allocation_status,created_by,created_on,current_doh,current_stock_pct,dept_desc,dept_nbr,inherit_global_decile,isvltrequired,item_type,last_updated_by,last_updated_on,margin_onhand,profit,sales_amt,sales_qty,sum_need_qty_cdf,sum_need_qty_legacy,tenant_id,total_oh_qty,wk_supply,wk_supply_legacy,category_config_id) values (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,default) [23505-224]] [insert into category_config (allocated_items,allocation_description,allocation_status,created_by,created_on,current_doh,current_stock_pct,dept_desc,dept_nbr,inherit_global_decile,isvltrequired,item_type,last_updated_by,last_updated_on,margin_onhand,profit,sales_amt,sales_qty,sum_need_qty_cdf,sum_need_qty_legacy,tenant_id,total_oh_qty,wk_supply,wk_supply_legacy,category_config_id) values (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,default)]; SQL [insert into category_config (allocated_items,allocation_description,allocation_status,created_by,created_on,current_doh,current_stock_pct,dept_desc,dept_nbr,inherit_global_decile,isvltrequired,item_type,last_updated_by,last_updated_on,margin_onhand,profit,sales_amt,sales_qty,sum_need_qty_cdf,sum_need_qty_legacy,tenant_id,total_oh_qty,wk_supply,wk_supply_legacy,category_config_id) values (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,default)]; constraint [PRIMARY KEY]

Using h2 version 2.2.224

Previously it was working fine. Is there any issue in Hibernate 6 with GenerationType.IDENTITY? BTW we are passing categoryConfigId as null while calling save the method. Also one more thing I haven't declared any explicit create table in h2 as it was not required in previous versions.

Generators of standard identity columns don't change their base value when you insert a row with explicitly specified value. That's why next generated value is still 1 and it conflicts with early inserted row.

If you inserted rows with values 1, 2, …, 6, you also need to adjust generator of this column:

ALTER TABLE category_config ALTER COLUMN category_config_id RESTART WITH 7;