@Entity(name = "Client")
	public static class Client {

		@Id
		@GeneratedValue
		private Long id;

		private String name;

		@Embedded
		private Log log = new Log();

		public Long getId() {
			return id;
		}

		public String getName() {
			return name;
		}

		public void setName(String name) {
			this.name = name;
		}

		public void setId(Long id) {
			this.id = id;
		}
	}

	@Entity(name = "User")
	@Table(name = "`User`")
	public static class User {
		@Id
		@GeneratedValue
		private Long id;

		@Column(length = 120, nullable = false)
		private String name;

		@ManyToOne(fetch = FetchType.LAZY)
		@JoinColumn(name = "`idClient`")
		private Client client;

		public Long getId() {
			return id;
		}

		public String getName() {
			return name;
		}

		public void setName(String name) {
			this.name = name;
		}

		public Client getClient() {
			return client;
		}

		public void setClient(Client client) {
			this.client = client;
		}
	}

	@Embeddable
	public static class Log {
		@Column(name = "`creationDate`", nullable = false)
		private OffsetDateTime creationDate;

		public OffsetDateTime getCreationDate() {
			return creationDate;
		}

		public void setCreationDate(OffsetDateTime creationDate) {
			this.creationDate = creationDate;
		}
	}

        @Test
	public void load() {
		inTransaction(
				session -> {
					User user = session.find( User.class, userId );
				}
		);
	}

org.hibernate.PropertyValueException: not-null property references a null or transient value : Client.log.creationDate