У вас есть 3 варианта.

ALWAYS
Indicates the value is generated on insert and on update.
INSERT
Indicates the value is generated on insert.
NEVER
Indicates the value is never generated.

@ Сгенерированная аннотация

GenerationTime.ALWAYS

GenerationTime.ALWAYS updates the entity at both time insert and update. In the case of GenerationTime.ALWAYS, the property should not be insertable and updatable.

@Generated(GenerationTime.ALWAYS)
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "modified_date", updatable = false, insertable = false)
private Date modifiedDate;

GenerationTime.INSERT

GenerationTime.INSERT updates the entity only at time of insertion . In the case of GenerationTime.INSERT, the property should not be insertable.

@Generated(GenerationTime.INSERT)
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "created_date", insertable = false) 
private Date createdDate;

GenerationTime.NEVER

GenerationTime.NEVER does not update the entity neither on update nor insert time.

@Generated(GenerationTime.NEVER)

@CreationTimestamp @UpdateTimestamp

Эти аннотации также могут использоваться каждым из следующих типов:

• java.time.LocalDate (начиная с Hibernate 5.2.3)
• java.time.LocalDateTime (начиная с Hibernate 5.2.3)
• java.util.Date
• java.util.Calendar
• java.sql.Date
• java.sql.Time

• java.sql.Timestamp

  @Column
  @CreationTimestamp
  private LocalDateTime createDateTime;
  
  @Column
  @UpdateTimestamp
  private LocalDateTime updateDateTime;