title: Spring Boot JPA @UpdateTimestamp not working with Postgresql
body: <p>I'm facing strange issue last modified date is not getting updated automatically.
  I'm using <strong>Postgresql Version 12.3</strong> and <strong>Springboot 2.2.4.RELEASE</strong>
  Here's my Entity Class</p>
  <pre><code>@Entity
  @Table(name = &quot;users&quot;)
  @org.hibernate.annotations.Entity(
          dynamicUpdate = true
  )
  @Data
  public class Users {
  
  
      @Id
      @GeneratedValue(generator = &quot;UUID&quot;)
      @GenericGenerator(
              name = &quot;UUID&quot;,
              strategy = &quot;org.hibernate.id.UUIDGenerator&quot;
      )
      @Column(updatable = false, nullable = false)
          private String userId;
  
          private String userName;
  
          private String userEmail;
  
          private String userPhoneNumber;
  
          @CreationTimestamp
          @Column(updatable = false)
          @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = &quot;yyyy-MM-dd HH:mm:ss&quot;, timezone = &quot;GMT+05:30&quot;)
          private Timestamp createdOn;
  
          @UpdateTimestamp
          @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = &quot;yyyy-MM-dd HH:mm:ss&quot;, timezone = &quot;GMT+05:30&quot;)
          private Timestamp lastUpdatedOn;
  
  }
  </code></pre>
  <p>Database Records:</p>
  <pre><code>            createdon        |      lastupdatedon
   2020-08-27 07:43:37.994 | 2020-08-27 07:43:37.994
   2020-08-07 07:49:22.797 | 2020-08-07 07:49:22.797
   2020-08-12 13:38:43.503 | 2020-08-12 13:38:43.503
  </code></pre>
  <p>You can see both createdOn and lastUpdatedOn are same. Even though the records updated frequently last modified date is not getting updated.</p>
  <p>I'm saving record with jpa repository
  ex:</p>
  <pre><code> usersRepository.save(user); 
  </code></pre>