Why Is Constructor Declared Private?

Can a constructor be virtual?

In C++, the constructor cannot be virtual, because when a constructor of a class is executed there is no virtual table in the memory, means no virtual pointer defined yet.

So, the constructor should always be non-virtual.

But virtual destructor is possible..

What happens if a user forgets to define a constructor inside a class?

What happens if a user forgets to define a constructor inside a class? Explanation: The C++ compiler always provides a default constructor if one forgets to define a constructor inside a class.

What is the benefit of copy constructor?

Copy constructors make it easy to copy objects. STL containers require all content to be copied and assigned. Copy constructors can be more efficient than copyfrom () solutions because they combine construction and replication.

What happens if a constructor is declared private?

If we declare a constructor as private we are not able to create an object of a class. We can use this private constructor in the Singleton Design Pattern.

Should a constructor be public or private?

No, Constructors can be public , private , protected or default (no access modifier at all). Making something private doesn’t mean nobody can access it. It just means that nobody outside the class can access it. So private constructor is useful too.

Can copy constructor be private?

Yes, a copy constructor can be made private. When we make a copy constructor private in a class, objects of that class become non-copyable.

Can we override private methods?

No, we cannot override private or static methods in Java. Private methods in Java are not visible to any other class which limits their scope to the class in which they are declared.

Can a constructor return a value?

No, constructor does not return any value. … In general, Constructor is implicitly called at the time of instantiation. And it is not a method, its sole purpose is to initialize the instance variables.

Why do we need copy constructor?

A copy constructor in a Java class is a constructor that creates an object using another object of the same Java class. That’s helpful when we want to copy a complex object that has several fields, or when we want to make a deep copy of an existing object.

How do I access a private constructor?

Another way of accessing a private constructor is by creating a public static method within this class and have its return type as its object. Yes, we can access the private constructor or instantiate a class with private constructor.

Can constructor be declared as final?

No, a constructor can’t be made final. A final method cannot be overridden by any subclasses. … But, in inheritance sub class inherits the members of a super class except constructors. In other words, constructors cannot be inherited in Java therefore, there is no need to write final before constructors.

Can a constructor be overloaded?

Yes! Java supports constructor overloading. In constructor loading, we create multiple constructors with the same name but with different parameters types or with different no of parameters.

Can a constructor be static?

No, we cannot define a static constructor in Java, If we are trying to define a constructor with the static keyword a compile-time error will occur. In general, static means class level. … We need to assign initial values for an instance variable we can use a constructor.