Is it possible to apply inheritance to a Singleton class?

Question

Today I faced one question in interview. Is it possible to apply inheritance concept on Singleton Classes? I said since the constructor is private, we cannot extend that Singlet

Answer 1

You could make the constructor package-private. This way, no classes outside the package could instantiate the Singleton class but derived classes could call the upper class constructor.

But, as others said, this is really not advisable.

Stupid interview question by the way.