Can We Override Constructor?

Can a class run without constructor?

Java doesn’t require a constructor when we create a class.

The compiler automatically provides a public no-argument constructor for any class without constructors.

This is called the default constructor.

If we do explicitly declare a constructor of any form, then this automatic insertion by the compiler won’t occur..

Can a constructor return a value?

No, constructor does not return any value. While declaring a constructor you will not have anything like return type. 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.

What is the role of constructor in inheritance?

Constructors have a special job of initializing the object properly. A Derived class constructor has access only to its own class members, but a Derived class object also have inherited property of Base class, and only base class constructor can properly initialize base class members.

Can we inherit constructor?

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.

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. A constructor will be used to assign initial values for the instance variables.

Can private constructor class inherited?

You are right if you are making class static then private constructor is of no use. … So private constructor + sealed means pure static class. Also sealed class cannot be inherited. then where to use sealed and where to use private constructor (as both class cannot be inherited).

Can we override static method?

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

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 you use this () and super () both in a constructor?

Both this() and super() are constructor calls. Constructor call must always be the first statement. So you either have super() or this() as first statement. Both this() and super() are constructor calls, and constructor call must be the first (and only first) call in a constructor.

How do you override a constructor?

Cannot override constructor. Constructor can be regarded as static, subclass cannot override its super constructor. Of course, you could call protected-method in super class constructor, then overide it in subclass to change super class constructor.

Can a constructor be final?

No, a constructor can’t be made final. A final method cannot be overridden by any subclasses. As mentioned previously, the final modifier prevents a method from being modified in a subclass. … In other words, constructors cannot be inherited in Java therefore, there is no need to write final before constructors.

Can static and final come together?

1)when we apply “static” keyword to a variable ,it means it belongs to class. static means there is only one copy of the variable in memory shared by all instances of the class. The final keyword just means the value can’t be changed. Without final , any object can change the value of the variable.

Can we override constructor in C++?

a constructor cannot be overridden. a constructor cannot be called with an object but method can be called. To call a constructor, an object must be created. … in method overriding, the super class method and subclass method should be of the same – same name, same return type and same parameter list.

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.

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.