Hotel Search System - spring-boot

Question

I need to build a hotel search spring boot application.
The issue that I was confused about is the hotel system objects must be build up in an object-oriented manner.
So I build up some objects, but the question is how will I search this in the JPA repository.
Mainly JPA works with one or two tables,
but in this case, I need to use all of the tables to return the result.
Do you recommend writing custom SQL for that?
And the second issue, how will I search for availability. I decided to keep the availability matrix per room because hotels can have several rooms.
Querying hotels, cities, etc. are easy but the date range in multiple rooms that a hotel keeps is the challenge?
How could I put this in my query in this case?
Thanks,
Regards.
City
package com.booking.hotel.entity;
import java.util.List;
import lombok.Data;
#Data
public class City {
private long id;
private String name;
List<Hotel> hotelList;
}
Hotel.java
package com.booking.hotel.entity;
import java.util.List;
import lombok.Data;
#Data
public class Hotel {
private String name;
private City city;
private int ranking;
private String location;
private int distanceToCenter;
private List<Room> roomList;
}
Room.java
package com.booking.hotel.entity;
import java.math.BigDecimal;
import java.util.Date;
import java.util.HashMap;
import lombok.Data;
#Data
public class Room {
private long id;
private long hotelId;
private String type;
private BigDecimal pricePerNight;
private int roomSize;
private boolean wiFi;
private boolean airCondition;
HashMap<Date, Boolean> availabilityHashMap;
private Room() {
// initialize room available by default
}
}