10. Abstract Abstract method parent (abstract) class contains only method definition each child branch must implement all abstract methods from abstract parent specific implementation in child class must not add the propagation of checked exception (no problem with unchecked exception) on the contrary, is it possible to hide checked exception in here Abstract class is the class with abstract modifier when trying to create instance of abstract class the compilation error will occur if at least one abstract method is contained in class the class must be abstract too on the contrary, the abstract class may have no abstract method