APCS Unit 10 Interfaces
What are interfaces used for?
-capturing similarities between unrelated classes without artificially forcing a class relationship -declaring method methods that one or more classes are expected to implement
______ are used to encode _______ which classes of various types share but do not necessarily constitute a __________.
Interfaces similarities relationship
Do interface types have instance fields?
No
Do interfaces have constructors? Why?
No because they can't be initiated
Can interfaces extend more than one interface?
Yes
Which of the following is true?
a child class can extend one parent and implement 0/more interfaces
What is an interface?
a collection of constants and method declarations
We use ____ _____ when an operation is performed in a different way for the subclasses forcing subclass to provide a ____ implementation.
abstract methods custom
When a class implements an interface, what must it do?
declare and provide a method body for each method in the interface
An interface is a way to _____ what classes should do, without specifying ___ they should do it.
describe how
Interface _____ a set of associated behaviors that can be used by _____ classes
encapsulates dissimilar
A class implementing an interface should use the keyword _____
implements
A class realizes (_______) an ______ by promising to provide the _________ for all of the methods in the interface.
implements interface implementation
A java __ declares methods that classes are expected to implement.
interface
Methods form the object's ______ with the outside world
interface
Use the keyword __ to define an interface
interface
you can define a reference of type _____ but you should assign to it an object instance of class type which ______ that interface
interface implements
In the computer world, the term ____ refers to any mechanism that connects ____ devices or entities and _______ the rules for their _______.
interface two defines interaction
An interface can be implemented by ___ class and a class can implement multiple _____.
many interfaces
Some object oriented languages allow ____ _______ which allows a class to be derived from ______ or more classes, inheriting the members of all parents.
multiple inheritance two
Can an interface ever contain method bodies?
no
Can object be created from an interface?
no
Interfaces contain __ _____ ______ and cannot be _______.
no instance fields instantiated
is it ok if a class definition implements two interfaces, each of which has the same definition for the constant PI?
no, if a class implements several interfaces, each constant must be defined in only one interface
can an interface be given the private access modifier?
no- the interface could never be used then
All methods in an interface are automatically _____ and _____.
public abstract
class definition with implementation of interface
public class Name implements Name
It's not a class but a set of ____ for classes that want to conform to the ____.
requirements interface
can an interface extends another?
yes
