Basic java programme to understand Abstract Class

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. An abstract class may have static fields and static methods. 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.

An abstract method is a method that is declared without an implementation (without braces and followed by a semicolon), like this:

abstract void sum(int a, int b);

Consider using abstract classes if any of these statements apply to your situation:

1. You want to share code among several closely related classes.
2. You expect that classes that extend your abstract class have many common methods or fields or require access modifiers other than public (such as protected and private).
3. You want to declare non-static or non-final fields. This enables you to define methods that can access and modify the state of the object to which they belong.

Example -

File name - Abstarct_Bank.java

Output -