Interface Implementation

• Implementation: class that implements ALL the methods (including those in in its super-interfaces); more than one implementation possible
• If not all methods implemented the implementing class must be shown abstract
• Interface Declaration, Instantiation and Use
• Interface and Inheritance: extending interface; super-interfaces; multiple interface inheritance allowed (``,'' delimited in declaration of implementing class)
• No inheritance relationships need exist between implementor classes in an interface hierarchy
• Interface name can be used as type of data
• Interface cannot grow: any change will make all existing implementations fail: make interface design future proof, add new interfaces incrementally
• Example:

interfaceName.constantName