What's the difference between an abstract class and interface in Java?
Abstract class can inherit another class using extends keyword and implement an interface. Interface can inherit only an inteface. Abstract class can be inherited using extends keyword. Interface can only be implemented using implements keyword.
What is abstract class in Java?
An abstract class is a class that is declared abstract —it may or may not include abstract methods. 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.
What is interface class in Java?
An interface is a reference type in Java. It is similar to class. It is a collection of abstract methods. A class implements an interface, thereby inheriting the abstract methods of the interface. Along with abstract methods, an interface may also contain constants, default methods, static methods, and nested types.
What is the use of abstract class and interface in Java?
An abstract class is used if you want to provide a common, implemented functionality among all the implementations of the component. Abstract classes will allow you to partially implement your class, whereas interfaces would have no implementation for any members whatsoever.
What is abstract class in OOP?
An abstract class is a class that contains at least one abstract method. An abstract method is a method that is declared, but not implemented in the code.
What is polymorphism in Java?
In Java, polymorphism refers to the ability of a class to provide different implementations of a method, depending on the type of object that is passed to the method. To put it simply, polymorphism in Java allows us to perform the same action in many different ways.
What is static in Java?
The static keyword is a non-access modifier used for methods and attributes. Static methods/attributes can be accessed without creating an object of a class.
What is array in Java?
An array is a container object that holds a fixed number of values of a single type. The length of an array is established when the array is created. After creation, its length is fixed.
What is inheritance in OOP?
Inheritance in OOP = When a class derives from another class. The child class will inherit all the public and protected properties and methods from the parent class. In addition, it can have its own properties and methods. An inherited class is defined by using the extends keyword.
Why interface is used in Java?
In Java, an interface specifies the behavior of a class by providing an abstract type. As one of Java's core concepts, abstraction, polymorphism, and multiple inheritance are supported through this technology. Interfaces are used in Java to achieve abstraction.
What is purpose of abstract class?
An abstract class cannot be instantiated. The purpose of an abstract class is to provide a common definition of a base class that multiple derived classes can share.
What is abstract class example?
Abstract classes are essential to providing an abstraction to the code to make it reusable and extendable. For example, a Vehicle parent class with Truck and Motorbike inheriting from it is an abstraction that easily allows more vehicles to be added.
What is abstract in Java with example?
Abstraction in Java Abstraction is a process of hiding the implementation details and showing only functionality to the user. Another way, it shows only essential things to the user and hides the internal details, for example, sending SMS where you type the text and send the message.
What is abstract class explain with example?
Abstract classes are essential to providing an abstraction to the code to make it reusable and extendable. For example, a Vehicle parent class with Truck and Motorbike inheriting from it is an abstraction that easily allows more vehicles to be added.
What is the use of 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 purpose of abstract class?
An abstract class cannot be instantiated. The purpose of an abstract class is to provide a common definition of a base class that multiple derived classes can share.