Can A Constructor Be Virtual?

Can constructor be virtual in Java?

If it is like virtual function in C++ there is no virtual constructor in java.

Not that I’m aware off.

All you have to do is simply set the constructor to private, and within the class, include a static method that creates the class object instance and returns it..

Can a constructor be private?

Yes, we can declare a constructor as 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.

Can 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 we override static method?

Can we Override static methods in java? We can declare static methods with the same signature in the subclass, but it is not considered overriding as there won’t be any run-time polymorphism. Hence the answer is ‘No’.

Why can’t a constructor be 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.

Why virtual constructor in C++ is not possible?

A virtual-table(vtable) is made for each Class having one or more ‘virtual-functions’. … Constructor can not be virtual, because when constructor of a class is executed there is no vtable in the memory, means no virtual pointer defined yet. Hence the constructor should always be non-virtual.

Can copy constructor be virtual in C++?

With the use of a virtual copy constructor, the programmer will be able to create an object without knowing the exact data type of the object. In C++ programming language, copy Constructor is used to creating an object copied from another.

Can you overload a virtual function?

In fact, virtual functions, as other functions, CAN be overloaded within the class defining them, in addition to the override option for derived classes. Even for pure virtual functions, they can have multiple signatures in abstract classes!

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).

Do you have to override a virtual function C++?

It is not mandatory for derived class to override (or re-define the virtual function), in that case base class version of function is used. A class may have virtual destructor but it cannot have a virtual constructor.

Why do we need virtual destructor?

To be simple, Virtual destructor is to destruct the resources in a proper order, when you delete a base class pointer pointing to derived class object. Virtual keyword for destructor is necessary when you want different destructors should follow proper order while objects is being deleted through base class pointer.

Can static function virtual?

A virtual function cannot be global or static because, by definition, a virtual function is a member function of a base class and relies on a specific object to determine which implementation of the function is called. You can declare a virtual function to be a friend of another class.

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.

Can a virtual function be called from constructor?

You can call a virtual function in a constructor, but be careful. It may not do what you expect. In a constructor, the virtual call mechanism is disabled because overriding from derived classes hasn’t yet happened. Objects are constructed from the base up, “base before derived”.

How do you call a virtual function?

A virtual function is a member function that you expect to be redefined in derived classes. When you refer to a derived class object using a pointer or a reference to the base class, you can call a virtual function for that object and execute the derived class’s version of the function.