The abstract classes and methods are used to create a model of minimum required methods which must be defined in normal sub-classes derived from an abstract class (with extends). An abstract class is created with the abstract keyword. An abstract class cannot be instantiated, can only be inherited by other sub-classes extended from it. The abstract methods are declared with the abstract keyword, and cannot have an implementation, they simply declare the method's signature. abstract public function methodName($arguments); Abstract methods are only created in an abstract class. 

Note :- You can not declare an abstract class as final, because abstract class means it has to be extended and final class means it can't be extended.