Question: Can We Instantiate An Abstract Class?

Can we declare abstract class as final?

In short, an abstract class cannot be final in Java, using both abstract and final modifier with a class is illegal in Java.

An abstract method must be overridden to be useful and called but when you make the abstract method final it cannot be overridden in Java, hence there would be no way to use that method..

Can you instantiate an abstract class and what is an inner class?

Infact annonymous inner type allows you to create a no-name subclass of the abstract class and an instance of this. Abstract classes cannot be instantiated – this is by definition and design.

Which method Cannot be overridden?

A method declared final cannot be overridden. A method declared static cannot be overridden but can be re-declared. If a method cannot be inherited, then it cannot be overridden. A subclass within the same package as the instance’s superclass can override any superclass method that is not declared private or final.

Can an abstract class extend concrete?

An abstract class always extends a concrete class ( java. lang. … If you want to instantiate it, you will have to subclass it with a concrete implementation of those abstract methods and instantiate it through the concrete class.

What is encapsulation in Oops ABAP?

Encapsulation is an Object Oriented Programming (OOP) concept that binds together data and functions that manipulate the data, and keeps both safe from outside interference and misuse. … ABAP supports the properties of encapsulation and data hiding through the creation of user-defined types called classes.

What is abstract class in Ooabap?

Added on June 22nd 2015 by Ashok Kumar Reddy. It is a class which contains methods with implementation as well as methods without implementation . (or) Abstract class is a class which contains at least one abstract method.

Can abstract class contain final method?

As a final class cannot be inherited. However, an abstract class can have a final method. This final method is treated like a normal method with a body which cannot be overridden.

Why can’t we instantiate an abstract class?

Because an abstract class is an incomplete class (incomplete in the sense it contains abstract methods without body and output) we cannot create an instance or object; the same way you say for an interface. You CAN instantiate an abstract class. You only need to provide a concrete subclass.

Can abstract class have constructor?

Yes! Abstract classes can have constructors! Yes, when we define a class to be an Abstract Class it cannot be instantiated but that does not mean an Abstract class cannot have a constructor. Each abstract class must have a concrete subclass which will implement the abstract methods of that abstract class.

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.

Does abstract method have body?

Abstract methods means there is no default implementation for it and an implementing class will provide the details. So, it’s exactly as the error states: your abstract method can not have a body. The reason you would do something like this is if multiple objects can share some behavior, but not all behavior.

Why do we need 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.

What is difference between abstract class and interface?

Classes can implement multiple interfaces, but only one abstract class. Abstract classes can contain non-abstract methods. They can both have methods, variables, and neither one can be instantiated. All variables declared in an interface are final, while an abstract class may contain non-final variables.

What is abstract class in ABAP OOPS?

Abstract Class is a special kind of class which can’t be instantiated. We can only instantiate the subclasses of the Abstract class if they are not abstract. Abstract class should at least contain one abstract method. Abstract methods are methods without any implementation – only a declaration.

Can we declare abstract class as static?

Yes, abstract class can have Static Methods. The reason for this is Static methods do not work on the instance of the class, they are directly associated with the class itself.

Can we instantiate abstract class in Ooabap?

we cannot create an object to the abstract class instead create an object to the child class and call the methods . Abstract class are mainly used for creating inheritance.

How do you instantiate an abstract class object in Java?

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.

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’.