ConcreteClasses.java

public class Circle implements Shape {
    @Override
    public String draw() {
        return "This is a circle !!!";
    }
}

public class Rectangle implements Shape {
    @Override
    public String draw() {
        return "This is a Rectangle !!!";
    }
}

public class Square implements Shape {
    @Override
    public String draw() {
        return "This is a Square !!!";
    }
}