If we want to create a SubClass to Abstract Class : - We have to extend that Abstract Class from our Class with the help of extend keyword. - We should implement all the Abstract Methods of Abstract Class in SubClass. In case if we not implement any one of Abstract Method in our SubClass we must and should declare our SubClass also as abstract. - Abstract Class reference variable can be used to refer Subclass's Objects. But we can't access the individual methods of SubClass. - A Class can't be both abstract and final.