Quick Answer: Why Return Type Is Not Allowed For Constructor?

Can we declare constructor as 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..

Is it compulsory to use constructor in a class?

It can be used to initialize the objects to desired values or default values at the time of object creation. It is not mandatory for the coder to write a constructor for a class. If no user-defined constructor is provided for a class, compiler initializes member variables to its default values.

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 type of constructor Cannot have a return type?

implicit return typeThe implicit return type by default is the class type in which it is declared. No. A constructor can not return a value because a constructor completely replaces the reference ID of an object, and as a constructor is also a method and a method can’t return more than one values.

Does constructor return any value in C++?

Constructors are functions that do not return a value. The family of functions that do not return a value consists of: void functions, constructors and destructors. It is stated in 6.6. 3/2 in the C++ standard.

What happens if we make a constructor 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.

Is constructor inherited?

A subclass inherits all the members (fields, methods, and nested classes) from its superclass. Constructors are not members, so they are not inherited by subclasses, but the constructor of the superclass can be invoked from the subclass.

How many constructor can a class have?

65535 constructorsYou can have 65535 constructors in a class(According to Oracle docs). But IMPORTANTLY keep this in your mind. We achieve this only by CONSTRUCTOR OVERLOADING ( https://beginnersbook.com/2013/05/constructor-overloading/ ). You can create many constructors but with different signatures.

Can we have return type for constructor?

No, constructor does not have any return type in Java. … It does not have a return type and its name is same as the class name. Mostly it is used to instantiate the instance variables of a class. If the programmer doesn’t write a constructor the compiler writes a constructors on his behalf.

Can constructor can take any number of parameters?

You can use any data type for a parameter of a method or a constructor. This includes primitive data types, such as doubles, floats, and integers, as you saw in the computePayment method, and reference data types, such as objects and arrays.

What is true constructor?

What is true about constructor? Explanation: Constructor returns a new object with variables defined as in the class. Instance variables are newly created and only one copy of static variables are created. … Explanation: No instance can be created of abstract class.

Why a return type is not allowed for constructor?

So the reason the constructor doesn’t return a value is because it’s not called directly by your code, it’s called by the memory allocation and object initialization code in the runtime. Its return value (if it actually has one when compiled down to machine code) is opaque to the user – therefore, you can’t specify it.

Why constructor has no return type not void?

Constructor is internally a nonstatic method with name and void return type. It does not return anything. … Object is not allocated with constructor itself. In other words the syntax new Object() not only calls the constructor but also creates new object and after calling the constructor returns it.

Can final method be overloaded?

private and final methods can be overloaded but they cannot be overridden. It means a class can have more than one private/final methods of same name but a child class cannot override the private/final methods of their base class.

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).

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.

What is a constructor method?

A constructor method is a special function that creates an instance of the class. Typically, constructor methods accept input arguments to assign the data stored in properties and return an initialized object. … A class can define a constructor method that overrides the default constructor.

What is the purpose of a 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. If all the methods in the class are static, consider making the complete class static.

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.

Why do we use constructor?

The purpose of constructor is to initialize the object of a class while the purpose of a method is to perform a task by executing java code. Constructors cannot be abstract, final, static and synchronised while methods can be. Constructors do not have return types while methods do.

Can we have more than one constructor in a class?

There can be multiple constructors in a class. However, the parameter list of the constructors should not be same. This is known as constructor overloading.