How to initialise array of parent class type?

Question

I have a class called SeatingPlan which inherits from Seat.

In the SeatingPlan constructor I'm initializing as:

public SeatingPlan(int numberOfRows, int numberOfColumns) {
   super();
   rows = numberOfRows;
   columns = numberOfColumns;
   seats = new Seat[rows][columns];  // (Seat [][] seats during variable declarations)
}

Seat.java:

public Seat(String subject, int number) {
   courseSubject = subject;
   courseNumber = number;
}

However I'm getting this error:

SeatingPlan.java:8: error: 
    constructor Seat in class Seat cannot be applied to given types;
        super();
        ^
      required: String,int
      found: no arguments
      reason: actual and formal argument lists differ in length
    1 error
    [ERROR] did not compile; check the compiler stack trace field for more info

Answer 1

Either you need a default empty constructor for Seat or you need to call super with the arguments super(subject, number)

Answer 2

Problem is, in Java when you overload the constructor default constructor won't be provided by the compiler automatically anymore. So, if you still need to make use of it then you need to define it in your class.

public class Seat{

    public Seat(){//Implement the no-arg constructor in your class


    }

    public Seat(String subject, int number) {
       courseSubject = subject;
       courseNumber = number;
    }

}

Now you can access the no-args constructor of parent class Seat through the SeatingPlan child class.

public SeatingPlan(int numberOfRows, int numberOfColumns) {
   super();//Now you can access the no-args constructor of Seat parent class
   rows = numberOfRows;
   columns = numberOfColumns;
   seats = new Seat[rows][columns];  // (Seat [][] seats during variable declarations)
}

Answer 3

You are calling super() while you don't have a default constructor that does not accept parameters. So, add the below constructor and it will work. Or add the required parameters in the super(param, param) call.

public Seat() {
}