[Solved] Inheritance vs. Delegation [duplicate]

by 


class B {
    int m() {
        return new A().m();
    }
}

or 

class B {
    private A a = new A();
    int m() {
        return a.m();
    }
}

or 

class B {
    private A a;

    public B(A a) {
        this.a = a;
    }

    int m() {
        return a.m();
    }
}

solved Inheritance vs. Delegation [duplicate]