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specification > interface

interface (abstract data type)
subject			fact

interface	is a synonym of abstract data type
	can contain abstract methods
	can extend 1 or more interfaces
	cannot have any concrete methods or instance variables
	defines a set of methods
	has definition In Java, a software module containing a description of a set of operations that certain classes must implement
	has definition A named collection of method declarations (without implementations), may also include constant declarations (variables marked static and final)
	has 1 fully qualified name that includes its package name
	has 1 simple name that does not include its package name
	has example public interface Drawable { public abstract Image drawImage(); public abstract Image drawImage(int height, int width); public abstract Image drawBlackAndWhiteImage(int height, int width); }
	has part interface definition
	has purpose to capture similarities between unrelated classes without artificially forcing a class relationship to declare methods that one or more classes are expected to implement to let you define a protocol of behaviour that can be implemented by any class anywhere in the class hierarchy to reveal an object's programming interface without revealing its class
	has syntax public interface InterfaceName extends SuperInterfaces { InterfaceBody }
	inherits all constants and methods from its superinterfaces unless the interface hides a constant with the same name or the interface redeclares a method with a new method declaration
	is like a class except that it does not have any executable statements - it only contains abstract methods and class variables
	is abstract by definition - the modifier is optional in the declaration
	is a member of the default package unless its source file contains a package statement
	is only accessible to classes that are defined in the same package unless the interface is public
	is a subtopic of Interfaces
	is compiled by the Java compiler into a .class file
	is implemented by 1 or more class
	is a kind of access unit
	is a kind of specification
	may have 1 or more superinterfaces
	may have access modifier public, or none
	provides many of the same benefits as multiple inheritance
	should be a member of 1 named package
access unit	has access mode
syntactic unit	has syntax rule bold = mandatory italic = non-terminal normal font = optional

Kinds of interface :

• Iterator (4 facts)
• Runnable (5 facts)
• Serializable (6 facts)

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