Object-oriented programming (OOPs) Question:

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What is a private constructor? Where will you use it?

OOP Interview Question
OOP Interview Question

Answer:

When you declare a Constructor with Private access modifier then it is called Private Constructor. We can use the private constructor in singleton pattern.

If you declare a Constructor as private then it doesn’t allow to create object for its derived class, i.e you loose inherent facility for that class.

Example:

Class A

{

// some code

Private Void A()

{

//Private Constructor

}

}



Class B:A

{

//code

}



B obj = new B();// will give Compilation Error



Because Class A constructor declared as private hence its accessibility limit is to that class only, Class B can't access. When we create an object for Class B that constructor will call constructor A but class B have no rights to access the Class A constructor hence we will get compilation error.

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