create table booking (
    id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT,
    user varchar(30) not null,
    reason varchar(200) not null,
    requestTime datetime not null,
    status varchar(1) not null,
    PRIMARY KEY (id)
);
create table bookingslot (
    id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT,
    startdate datetime not null,
    status varchar(1) not null,
    bookingId smallint not null,
    facilityId smallint not null,
    PRIMARY KEY (id)
);

@Entity
@Table(name="booking")
public class Booking {
   @GeneratedValue (strategy=GenerationType.AUTO)
   @Id
   int id;
   String user;
   String reason;
   String status;
   Date requestTime;

   
   @OneToMany(cascade = {CascadeType.REMOVE}, mappedBy="booking", fetch = FetchType.LAZY)   
   Set<BookingSlot> bookingslot = new HashSet<BookingSlot>();
   
   
   @Column(name="id")
   public int getId() {
      return id;
   }
   public void setId(int id) {
      this.id = id;
   }
   @Column(name="user")
   public String getUser() {
      return user;
   }
   public void setUser(String user) {
      this.user = user;
   }
   @Column(name="reason")
   public String getReason() {
      return reason;
   }
   public void setReason(String reason) {
      this.reason = reason;
   }
   @Column(name="status")
   public String getStatus() {
      return status;
   }
   public void setStatus(String status) {
      this.status = status;
   }

   public Set<BookingSlot> getBookingSlot() {
      return bookingslot;
   }
   public void setBookingSlot(Set<BookingSlot> slots) {
      this.bookingslot = slots;
   }
   
   @Column(name="requestTime")
   public Date getRequestTime() {
      return requestTime;
   }
   public void setRequestTime(Date requestTime) {
      this.requestTime = requestTime;
   }
   
   
}

@Entity
@Table(name="bookingslot")
public class BookingSlot {
    int id;
   Date startDate;
   String status;

   @JoinColumn(name = "bookingId")
    @ManyToOne(optional = true)
    @ForeignKey(name = "bookingId")
   Booking booking;
   
   @Id
   @Column(name="id")
   @GeneratedValue (strategy=GenerationType.AUTO)
   public int getId() {
      return id;
   }
   public void setId(int id) {
      this.id = id;
   }
   
   @Column(name="startdate")
   public Date getStartDate() {
      return startDate;
   }
   public void setStartDate(Date startDate) {
      this.startDate = startDate;
   }

   @Column(name="status")
   public String getStatus() {
      return status;
   }
   public void setStatus(String status) {
      this.status = status;
   }
   
   
    public Booking getBooking() {
      return booking;
   }
   public void setBooking(Booking booking) {
      this.booking = booking;
   }
   

   /*@ManyToOne
   @JoinColumn(name = "facilityId")
   Facility facility;

    public Facility getFacility() {
      return facility;
   }
   public void setFacility(Facility facility) {
      this.facility = facility;
   }*/
}

Initial SessionFactory creation failed.
org.hibernate.MappingException: Could not determine type for: com.hsbc.ilab.booking.vo.Booking, at table: bookingslot, for columns: [org.hibernate.mapping.Column(booking)]
   at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:304)
...