Java: Issue Reading Text file then Converting

I've got an issue getting a method to read a file, then converting it to an integer. Here is a brief explanation of the program. It is essentially a car dealership inventory that keeps track of the vehicles in the lot by keeping them written down in a text file. When the program starts it will need to read the file and put all the current cars into an array so they can be displayed. Then the rest of the program will do other things like remove cars and add news ones etc. The part I am at is when the program first starts it needs to read the file, but I can't seem to get it to work.

The text file consists of 6 lines in total; 4 numbers first then 2 words respectively. I want the method to read the first four lines and convert those into integers and store them in a temporary array. Then after that it will read the next two lines and store those in a temporary array as well. Afterwards I take all these stored values and send them to a constructor. The constructor is then stored in an Arraylist and the Arraylist can be accessed anytime. In the output it does all of this just fine. But it wants to run through the method a second time despite barriers in place to prevent this.

Here is the code. Its a class and not the main program. I will try to explain the program as best I can inside the code.

public class Vehicle {

    //All the different private variables for the constructors and methods
    private int intholder[], year, type, kilometres, price, loop;
    private String make, model, myline, holder[]; 

    //The Arraylist that the different vehicle objects will be stored
    ArrayList<Vehicle> allCars = new ArrayList<Vehicle>();

    //The Default constructor
    public Vehicle(){
        make = "Vehicle Make";
        model = "Vehicle Model";
        type = 0;
        year = 0;
        kilometres = 0;
        price = 0;
    }

    //The constructor that has information sent to it
    public Vehicle(int _type, int _year, int _kilometres, int _price, String _make, String _model){
        make = _make;
        model = _model;
        type = _type;
        year = _year;
        kilometres = _kilometres;
        price = _price;
    }
    //Text file information
    /*
    * CAR TYPE CODE:
    * 1 - Sedan
    * 2 - Truck
    * 3 - Crossover
    * 4 - SUV
    * 5 - Sports
    * 
    * There is a total of 6 lines for each car and are as follows
    * 1 - int Type integer
    * 2 - int Year
    * 3 - int Kilometres
    * 4 - int Asking price
    * 5 - String Make
    * 6 - String Model
    */

    //The method in question. It reads through the file, converts the integers and stores them, 
    //stores the strings, and sends all the information to the constructor
    public void readCars()throws IOException{
        BufferedReader readFile = new BufferedReader(new FileReader("C:/Users/David/Desktop/FinalProject/Carlot.txt"));

        //Setting the length of the temporary arrays
        holder = new String[2];
        intholder = new int[4];

        //The main loop in the method. 
        do{

            //Read the first 4 lines of the file and convert them to integers. 
            //The try catch shouldn't have to be there because the first 4 lines 
            //of the file are all numbers, but I put it in there to see when it was messing up.
            for(int i = 0; i < 4; i++){
                myline = readFile.readLine();
                try{
                    intholder[i] = Integer.parseInt(myline);
                }
                catch(NumberFormatException e){
                    System.out.println(e);
                }

                //Had this in here to see how many lines down the file it would go before messing up.
                System.out.println(myline);
            }

            //Loop to store the Strings
            for(int i = 0; i < 2; i++){
                myline = readFile.readLine();
                holder[i] = myline;
                System.out.println(myline);
            }

            //Sends all the data to the constructor
            Vehicle V = new Vehicle(intholder[0], intholder[1], intholder[2], intholder[3], holder[0], holder[1]);

            //Several if statements to determine which subclass of vehicle it is.
            if(intholder[0]==1){
                Sedan S = new Sedan();
                allCars.add(S);
            }
            else if(intholder[0]==2){
                Truck T = new Truck();
                allCars.add(T);
            }
            else if(intholder[0]==3){
                Crossover C = new Crossover();
                allCars.add(C);
            }
            else if(intholder[0]==4){
                SUV U = new SUV();
                allCars.add(U);
            }
            else if(intholder[0]==5){
                Sports P = new Sports();
                allCars.add(P);
            }

        //Only break the loop if the myline equals null
        }while(myline != null);

        //if the loop breaks, close the file    
        readFile.close();
    }

Now I think I know where it is going wrong. At the end of the do/while, it checks if "myline" is null. And because the last time it read the file it was still a String the loop continues. The last time it goes through the loop, everything is null so trying to convert the integer is impossible so I get errors. But I have no idea how to get it to read the file at the end of the loop without going to the next line. Here is what the text file looks like.

1
2007
150250
5000
Toyota
Corolla
2
2005
240400
4500
Chevorlet
Silverado

I can't have it read at the end of the loop because if it does and there are still more cars after the one I just did, It goes into the next line when the loop restarts everything is thrown off.

Any help is appreciated, Thanks!