ls loose coupling can be achieved by any other manner rather than using parent class reference variable, in general not specifically in mine code?

Question

Tight coupling is when a group of classes are highly dependent on one another.

class C {
    A a;

    C(B b) {
      a = b;
    }
}

Interface A {
}

class B implements A {
}

In my code I am accepting object of class through reference of class B not by parent interface A.

1. Is my code loosely or tightly coupled?

   Loose coupling is achieved by means of a design that promotes single-responsibility and separation of concerns.

2. using the reference of parent class or interface make code more flexible to adopt any child class's object but how does it promotes single-responsibility.

3. Is loose coupling can be achieved by any other manner rather than using parent class reference variable, in any case not specifically in mine code?

Answer 1

This feels homeworky, but here is my answer.

The code is tightly coupled because the constructor for C depends upon B instead of the interface A. If you wanted to decouple C from B, you would accept an instance of A instead of B.

Loosely Coupled Code

class C {
    A a;

    C(A a) {
      this.a = a;
    }
}