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 Singleton class.

Next thing he asked me is to apply inheritance on that Singleton class. So, I made the Singleton's constructor as protected thinking that child's constructor also has be protected. But I was wrong the child can have a modifier either equal to or higher than that.

So, I asked him to give a real world example on such a case. He was not able to give me one and said that I cant ask questions and wanted me to tell whether this scenario is possible or not.

I went kind of blank. My question here is,

  • Is this possible?
  • Even if it is possible, what is the use of it?
  • What real world scenario would demand such a use?
java design-patterns singleton
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