Why abstract classes Cannot be instantiated?

We cannot instantiate an abstract class in Java because it is abstract, it is not complete, hence it cannot be used.

Can abstract classes be instantiated?

Abstract classes cannot be instantiated, but they can be subclassed. When an abstract class is subclassed, the subclass usually provides implementations for all of the abstract methods in its parent class. However, if it does not, then the subclass must also be declared abstract .

What does it meaning abstract class Cannot be instantiated?

An abstract class cannot be instantiated directly, i.e. the object of such class cannot be created directly using the new keyword. An abstract class can be instantiated either by a concrete subclass or by defining all the abstract method along with the new statement. It may or may not contain an abstract method.

Why can't we instantiate an abstract class in C?

We can't instantiate an abstract class because the motive of abstract class is to provide a common definition of base class that multiple derived classes can share.

Why abstract class has no object creation?

Because it's abstract and an object is concrete. An abstract class is sort of like a template, or an empty/partially empty structure, you have to extend it and build on it before you can use it.

Why Abstract Classes cannot be instantiated in C# ?

Can we declare a class as static?

So, Yes, you can declare a class static in Java, provided the class is inside a top-level class. Such clauses are also known as nested classes and they can be declared static, but if you are thinking to make a top-level class static in Java, then it's not allowed.

Can we inherit abstract class?

An abstract class cannot be inherited by structures. It can contains constructors or destructors. It can implement functions with non-Abstract methods.

Why can't we instantiate an interface?

You can't instantiate an interface or an abstract class because it would defy the object oriented model. Interfaces represent contracts - the promise that the implementer of an interface will be able to do all these things, fulfill the contract.

Why does abstract class have constructor?

The main purpose of the constructor is to initialize the newly created object. In abstract class, we have an instance variable, abstract methods, and non-abstract methods. We need to initialize the non-abstract methods and instance variables, therefore abstract classes have a constructor.

Can we have constructor in abstract class?

Like any other classes in Java, abstract classes can have constructors even when they are only called from their concrete subclasses.

What is the implementation to ensure that abstract classes never be instantiated?

Abstract classes are classes that contain one or more abstract methods. An abstract method is a method that is declared, but contains no implementation. Abstract classes cannot be instantiated, and require subclasses to provide implementations for the abstract methods.

Why abstract and static Cannot be used together?

A static method belongs to class not to object instance thus it cannot be overridden or implemented in a child class. So there is no use of making a static method as abstract.

Can interface be instantiated?

An interface can't be instantiated directly. Its members are implemented by any class or struct that implements the interface. A class or struct can implement multiple interfaces.

Why interface is better than abstract class?

The short answer: An abstract class allows you to create functionality that subclasses can implement or override. An interface only allows you to define functionality, not implement it. And whereas a class can extend only one abstract class, it can take advantage of multiple interfaces.

Can we declare interface method as static?

No, we cannot declare interface methods as static because static methods can not be overridden.

Can abstract methods have a body?

Abstract methods are declaration only and it will not have implementation. It will not have a method body. A Java class containing an abstract class must be declared as abstract class. An abstract method can only set a visibility modifier, one of public or protected.

Can 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 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. The main intention of making a method final would be that the content of the method should not be changed by any outsider.

Can constructor be static?

A static constructor is used to initialize any static data, or to perform a particular action that needs to be performed only once. It is called automatically before the first instance is created or any static members are referenced.

Can we declare abstract method as static?

Declaring abstract method static

If you declare a method in a class abstract to use it, you must override this method in the subclass. But, overriding is not possible with static methods. Therefore, an abstract method cannot be static.

Can we instantiate interface and abstract class?

No you can not instantiate an interface or abstract class. But you can instantiate an anonymous class that implements/extends the interface or abstract class without defining a class object.

What class Cannot be instantiated?

An abstract class cannot be instantiated.

Can we inherit private class?

Members of a class that are declared private are not inherited by subclasses of that class. Only members of a class that are declared protected or public are inherited by subclasses declared in a package other than the one in which the class is declared. The answer is No. They do not.

Can abstract class have main () function defined inside it?

Can abstract class have main() function defined inside it? Explanation: This is a property of abstract class. It can define main() function inside it. There is no restriction on its definition and implementation.

Can abstract class be initiated by new operator?

Explanation: Every class containing abstract method must be declared abstract. Abstract class cannot be directly initiated with 'new' operator and it cannot be initiated.