Abstract Class With Subclasses

Subclasses derived from a specific abstract base class must implement the methods and properties provided in that abstract base class.

Abstract class with subclasses. Other classes extend abstract classes. Its subclasses which include hashmap treemap and concurrenthashmap share many methods including get put isempty containskey and containsvalue that abstractmap defines. It cannot be instantiated. We have inherited a subclass dog from the superclass animal.

When we want to provide a common interface for different implementations of a component we use an abstract class. An abstract class serves as a basis that is a superclass for a group of related subclasses. That means the employee class is the superclass of the fulltimeemployee class. By defining an abstract base class you can define a common application program interface api for a set of subclasses.

An abstract class is as abstract as they come an unfinished blank for a group of future classes. The fulltimeemployee class is the child of the. The class contains an abstract method makesound and a non abstract method eat. Otherwise an error is raised during the object instantiation.

We then created an object d1 of dog. It can have abstract and non abstract methods. The fulltimeemployee class also inherits all the methods that are declared in the employee class setname getname setjobtitle getjobtitle and cutcheckthe fulltimeemployee class is a subclass of the employee class. Why use abstract base classes.

Here the subclass dog overrides the abstract method displayinfo. Instead they are inherited and extended by the concrete subclasses. Abstract classes cant be instantiated only subclassed. An abstract class must be declared with an abstract keyword.

Example of abstract class. An abstract class can define abstract properties and methods that subclasses implement. While we are designing large functional units we use an abstract class. Can have both abstract and concrete methods.

The blank cant be used as is. It can have final methods which will force the subclass not to change the body of the method. Similar to interfaces but 1 can implement methods 2 fields can have various access modifiers and 3 subclasses can only extend one abstract class. You can also talk in terms of blood relatives.

Abstract base classes cannot be instantiated. Implementing a concrete subclass. But it describes certain state and general behavior that will be possessed by future classes that inherit the abstract class.