Is it possible to merge multiple non persisted child entities at once?

I am trying to save multiple new entities to the database via a parent entity cascadeType. The structure is as follows:

Machine (cascadeType ALL defined here)

• ProductLinkBox

ProductLinkBox (cascadeType ALL defined here)

• ProductLinkMetaData

ProductLinkMetaData (cascadeType ALL defined here)

• FirmwareMetaData

In the end I call MachineRepository.save on the machine object. The Machine and ProductLinkBox object is successfully persisted, but nothing else. Do I need to manually persist all of the other types as well? Is hibernate not able to automatically persist all of the other parent - child relations?

Machine.java

@Entity
@Getter
@Setter
@NoArgsConstructor
@Table(name = "TAB_MACHINE")
public class Machine extends AbstractEntity {

  @Id
  @Column(name = "ID")
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "machineIdGenerator")
  @SequenceGenerator(
      name = "machineIdGenerator",
      sequenceName = "SEQ_MACHINE_ID",
      allocationSize = 1,
      initialValue = 10)
  Long id;


  @OneToMany(cascade = CascadeType.ALL, mappedBy = "machine", fetch = FetchType.LAZY, orphanRemoval = true)
  private List<ProductLinkBox> productLinkBoxes;

ProductLinkBoxes.java

@Entity
@Getter
@Setter
@NoArgsConstructor
@Table(name = "TAB_PRODUCT_LINK_BOX")
public class ProductLinkBox extends AbstractEntity {

  @Id
  @Column(name = "ID")
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "productLinkBoxIdGenerator")
  @SequenceGenerator(
      name = "productLinkBoxIdGenerator",
      sequenceName = "SEQ_PRODUCT_LINK_BOX_ID",
      allocationSize = 1,
      initialValue = 10)
  Long id;

  @ManyToOne
  @JoinColumn(name = "MACHINE_ID")
  private Machine machine;

  @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "productLinkBox")
  private ProductLinkMetaData productLinkMetaData;

ProductLinkMetaData.java

@Entity
@Getter
@Setter
@NoArgsConstructor
@Table(name = "TAB_PRODUCT_LINK_META_DATA")
public class ProductLinkMetaData extends AbstractEntity {

  @Id
  @Column(name = "ID")
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "productLinkMetaDataIdGenerator")
  @SequenceGenerator(
      name = "productLinkMetaDataIdGenerator",
      sequenceName = "SEQ_PRODUCT_LINK_META_DATA_ID",
      allocationSize = 1,
      initialValue = 10)
  Long id;

  @OneToOne(fetch = FetchType.LAZY)
  @JoinColumn(name = "PRODUCT_LINK_BOX_ID")
  @MapsId
  private ProductLinkBox productLinkBox;

  @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "productLinkMetaData")
  private FirmwareMetaData firmwareMetaData;

FirmwareMetaData.java

@Entity
@Getter
@Setter
@NoArgsConstructor
@Table(name = "TAB_FIRMWARE_META_DATA")
public class FirmwareMetaData extends AbstractEntity {

  @Id
  @Column(name = "ID")
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "firmwareMetaDataIdGenerator")
  @SequenceGenerator(
      name = "firmwareMetaDataIdGenerator",
      sequenceName = "SEQ_FIRMWARE_META_DATA_ID",
      allocationSize = 1,
      initialValue = 10)
  Long id;

  @OneToOne(fetch = FetchType.LAZY)
  @JoinColumn(name = "PRODUCT_LINK_META_DATA_ID")
  @MapsId
  private ProductLinkMetaData productLinkMetaData;

EDIT: Solved by following Vlad Mihalceas OneToOne mapping instructions in combination with the code from his github link.

Solved by following Vlad Mihalceas OneToOne mapping instructions in combination with the code from his github link. Removing the unnecessary ID mappings from the entities and using a shared PK did the trick.