Can Constructor Be Private?

What happens if constructor is private?

4 Answers.

It means that (without reflection) constructor wont be accessible outside of your class so other classes wont be able to call it.

Only members of your class will be bale to create its object..

Can constructor be static or final?

The static , final and abstract keywords are not meaningful for a constructor because: static members belong to a class, but the constructor is needed to create an object. An abstract class is a partially implemented class, which contains abstract methods to be implemented in child class.

Can constructor be overridden?

Constructor looks like method but it is not. It does not have a return type and its name is same as the class name. But, a constructor cannot be overridden. If you try to write a super class’s constructor in the sub class compiler treats it as a method and expects a return type and generates a compile time error.

Can constructor throw exception?

Yes, constructors are allowed to throw an exception in Java. A Constructor is a special type of a method that is used to initialize the object and it is used to create an object of a class using the new keyword, where an object is also known as an Instance of a class.

Can private constructor class inherited?

If class with private constructor and sealed class cannot be inherited , then what is the use of class which cannot be inherited. … And as said previously private constructor can be excused as we have static classes now. So private constructor + sealed means pure static class. Also sealed class cannot be inherited.

What is difference between static constructor and private constructor?

Static Constructor executes by the CLR not by the object of a class. … However, Private Constructor is used to restrict a class to be instantiated and to be inherited. Private Constructor is used whenever a class contains only static members.

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 constructor be private in CPP?

Yes, a constructor can be private. And you can call it with member functions (static or non) or friend functions. For possible use cases, see the Factory Pattern, or the Named Constructor Idiom.

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.

Are constructors always public?

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. … Using private constructor we can ensure that no more than one object can be created at a time.

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 be final?

No, a constructor can’t be made final. A final method cannot be overridden by any subclasses. … In other words, constructors cannot be inherited in Java therefore, there is no need to write final before constructors.

What is the purpose of private constructor?

Private constructors are used to prevent creating instances of a class when there are no instance fields or methods, such as the Math class, or when a method is called to obtain an instance of a class.

Why we Cannot make constructor final?

A constructor is never inherited to an another class so it doesn’t need to be marked final. Hey, The constructor cannot be final because the constructor cannot be inherited and in constructor values are initialized to the variable so by this variables changes every time and yes it cannot be inherited.

Can a constructor be static?

A static constructor does not take access modifiers or have parameters. A class or struct can only have one static constructor. Static constructors cannot be inherited or overloaded. A static constructor cannot be called directly and is only meant to be called by the common language runtime (CLR).

Why do we use constructor overloading?

If we want to have different ways of initializing an object using different number of parameters, then we must do constructor overloading as we do method overloading when we want different definitions of a method based on different parameters.