Extra Car Simulation

import java.util.*;

public class Car {
    
    private String carBrand;
    private String modelName;
    private String startingYear;
    private int carMileage = 0;
    private final int CURRENTYEAR = 2023; 

    private int carId = 0;
    private static int carsForSale = 0;
    private static ArrayList<Car> carsInMarket = new ArrayList<Car>();    

    /**
     * Constructor with 3 arguments
     * @param carBrand
     * @param modelName
     * @param startingYear
     * 
     * everytime this method is called, car id is added and a new car is added to the array
     */
    public Car(String carBrand, String modelName, 
    String startingYear, 
    int carMileage){
        this.carBrand = carBrand;
        this.modelName = modelName;
        this.startingYear = startingYear;
        this.carMileage = carMileage;
        carId = uniqueID();
        Car.carsInMarket.add(this);
    }

    /**
     * 
     * @return number of cars
     */
    public static int getCarsCount(){
        return Car.carsInMarket.size();
    }

    /**
     * 
     * @return unique id for each car
     */
    private int uniqueID(){
        Random randid = new Random();
        carId = randid.nextInt(9999);
        return carId;
    }

    /**
     * 
     * @return calling the car array
     */
    public static List<Car> getCarsInMarket(){
        return Car.carsInMarket;
    }
    
    public int getMarketLife(){
        return CURRENTYEAR - startingYear;
    }

    public void ageMarketLife() { 

        this.life -= Book.YEAR;  // remove a year
        if (getShelfLife() < 0.1) // small number zero out, this is for double floating point condition
            this.life = this.created;
    }

    public void setMarketLife(int years)

    /**
     * printing the object
     */
    public String toString(){
        return "Id: " + carId +  " Brand: " + carBrand + " Model: " + modelName + 
        " Year: " + startingYear + 
        " Mileage: " + carMileage;
    }

    public static void main(String[] args){

        System.out.println("Car available: " + Car.getCarsCount());

        Car BMWX1 = new Car("BMW","X1",30);

        Car HondaCRV = new Car("Honda","CRV",40);


        for(int i = 0; i < Car.getCarsCount(); i++){
            System.out.println((Car.getCarsInMarket().get(i)));
        }

        System.out.println("Car available: " + Car.getCarsCount());
        
    } 
}

Car.main(null);

Car available: 0
Id: 4722 Brand: BMW Model: X1 Mileage: 30
Id: 5579 Brand: Honda Model: CRV Mileage: 40
Car available: 2

public class ElectricCar extends Car{

    private int numBatteries;
    private long chargeTime;
    private boolean hasGear;

    public ElectricCar(String carBrand, String modelName, String startingYear, int carMileage, int numBatteries, long chargeTime){
        super(carBrand, modelName, startingYear, carMileage);
        this.numBatteries = numBatteries;
        this.chargeTime = chargeTime;
        
    }

    public void setHasGear(boolean hasGear){
        this.hasGear = hasGear;
    }

    public boolean getHasGear(){
        return hasGear;
    }

    

}