Title: Key Concept - Abstract Classes and Methods
Course: CPS 189: Java Certification - Review, Practice & Prepare (Development) > Section: (OLDstyle) Learning Modules

An abstract class

- It is a class that cannot be instantiated but can be subclassed.
- It may or may not include abstract methods. If a class has any abstract methods, it must be declared abstract.
- It contains the keyword abstract in its declaration.

● When an abstract class is subclassed, the subclass can define implementations for all of the abstract methods in the superclass. If it does not, then the subclass must also be declared abstract.

● A concrete method is a method that is declared with an implementation (curly braces enclosing statements, followed by a semicolon).

An abstract method

- It is a method that is declared without an implementation.
- It contains the keyword abstract in its declaration

For more information about abstract classes and methods:

- Click this link to view Oracles's documentation: abstract classes and methods.