Is it possible to create a proxy for class A using class B?

Yes, it is possible to create a proxy for class A using class B. In this case, class B acts as an intermediary that holds a reference to an object of class A and overrides the necessary methods, adding additional logic (such as logging, caching, access control) before or after calling the methods of class A.

Example in Java:

class A {
    void doSomething() {
        System.out.println("Executing A");
    }
}

class B {
    private A a;

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

    void doSomething() {
        System.out.println("Proxy B: before calling A");
        a.doSomething();
        System.out.println("Proxy B: after calling A");
    }
}

// Usage:
A a = new A();
B proxy = new B(a);
proxy.doSomething();

Thus, class B serves as a proxy for class A, extending or controlling its behavior.