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Can we achieve abstraction without abstract class and interface?
We can achieve 100% abstraction using interfaces. Abstract classes and Abstract methods : Any class that contains one or more abstract methods must also be declared with abstract keyword. There can be no object of an abstract class.
How does abstract class achieve abstraction?
If we want to use an abstract class, we have to inherit it from the base class. If the class does not have the implementation of all the methods of the interface, we should declare the class as abstract. It provides complete abstraction. It means that fields are public static and final by default and methods are empty.
Does an abstract class need an interface?
Abstract classes are similar to interfaces. You cannot instantiate them, and they may contain a mix of methods declared with or without an implementation. However, with abstract classes, you can declare fields that are not static and final, and define public, protected, and private concrete methods.
Does a class need to be abstract to be extended?
An abstract class must be extended and in a same way abstract method must be overridden. 4) A class has to be declared abstract to have abstract methods.
What is abstraction real world example?
Abstraction means displaying only essential information and hiding the details. Data abstraction refers to providing only essential information about the data to the outside world, hiding the background details or implementation. Consider a real life example of a man driving a car. This is what abstraction is.
Can abstract class can extend another class?
An abstract class can extend another abstract class. And any concrete subclasses must ensure that all abstract methods are implemented. Abstract classes can themselves have concrete implementations of methods. These methods are inherited just like a method in a non-abstract class.