Best answer: Why are constructors protected?

The reason for making the constructor protected, rather than private, is the same as for making any other method or field protected instead of private: so that it can be inherited by children.

Why we use protected constructor?

A protected constructor can be used to make a class effectively abstract when none of its methods are pure-virtual. It is not quite abstract in the C++ sense since friend classes can still use it without overriding, but then you would have to declare these.

Should constructors be protected?

Even if you do have the need for purely virtual methods within this coin class it is still good practice to keep the constructor protected. This makes the source more readable to others when they are looking at your class interface and they see a protected constructor.

Why we use protected constructor in Java?

Protecting a constructor prevents the users from creating the instance of the class, outside the package. During overriding, when a variable or method is protected, it can be overridden to other subclass using either a public or protected modifier only.

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Why protected constructors are used in abstract class?

An abstract class by definition cannot be instantiated directly. It can only be instantiated by an instance of a derived type. Therefore the only types that should have access to a constructor are its derived types and hence protected makes much more sense than public. It more accurately describes the accessibility.

What is the true about protected constructor?

What is true about protected constructor? Explanation: Protected access modifier means that constructor can be accessed by child classes of the parent class and classes in the same package. … Explanation: “this” is an important keyword in java.

What happens when a constructor is defined as protected?

A protected constructor means that only derived members can construct instances of the class (and derived instances) using that constructor.

Are there any kind of protected constructors?

A protected constructor can be accessed by a class instance creation expression (that does not declare an anonymous class) or a method reference expression only from within the package in which it is defined.

Can constructor be declared as protected in Java?

Modifiers public, protected and, private are allowed with constructors. We can use a private constructor in a Java while creating a singleton class.

Can a constructor be protected in C++?

Typically, constructors have public accessibility so that code outside the class definition or inheritance hierarchy can create objects of the class. But you can also declare a constructor as protected or private . Constructors may be declared as inline , explicit, friend or constexpr.

Why Singleton constructor is protected?

It’s so that subclasses can instantiantiate the Singleton base class, returning it as a part of itself in it’s own GetInstance() -type function. … Instead of having Instance define the set of possible singleton classes, the singleton classes can register their singleton instance by name in a well-known registry.

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What is the use of protected keyword in Java?

2. The protected Keyword. While elements declared as private can be accessed only by the class in which they’re declared, the protected keyword allows access from sub-classes and members of the same package.

Can we inherit protected class in Java?

The protected access modifier is accessible within the package. However, it can also accessible outside the package but through inheritance only. We can’t assign protected to outer class and interface.

Should the constructors in an abstract class be protected?

It makes little sense to have the public modifier on an abstract class constructor. After all, an abstract class cannot be created directly – only via a derived instance. … Hence, ReSharper recommends that you make the constructor protected .

Should abstract class be protected?

Yes, you can declare an abstract method protected. If you do so you can access it from the classes in the same package or from its subclasses. (Any you must to override an abstract method from the subclass and invoke it.)

What is the use of protected constructor in C#?

You can declare a constructor as private to prevent client code from directly instantiating an object. But then you can no longer subclass the class, because the derived class won’t have access to the constructor.