liskow substitution

class Employee {
    public int computeSalary() {
        return 1000;
    }
    final void doTheJob() {
        System.out.println("WORK!");
    }
}

interface IEmpWithBonus {
    default int getBonusSalary() {
        return 100;
    }
}

class PermanentEmployee extends Employee implements IEmpWithBonus {
    @Override
    public int computeSalary() {
        return super.computeSalary() * 2;
    }
}

class Intern extends Employee {
    @Override
    public int computeSalary() {
        return super.computeSalary() / 2;
    }
}

public class Main {

    public static void main(String[] args) {
        PermanentEmployee permanentEmployee = new PermanentEmployee();
        System.out.println(permanentEmployee.getBonusSalary());
        Intern intern = new Intern();
        System.out.println(intern.computeSalary());
    }
}