JAVA interface mechanism

interface

• Describe what functions the class has, without giving a specific implementation
• The keyword is interface
• A class can implement one or more interfaces
  • Does java support multiple inheritance, the answer is no java does not support multiple inheritance
• All methods in the interface are automatically public

Characteristics of the interface

• The interface is not a class and cannot be instantiated,
  • Abstract classes cannot be instantiated
• Can declare variables of interface type
  • Abstract classes can also declare variables of abstract types
• This variable must refer to an object that implements this interface
  • Abstract class variables must refer to objects that inherit this abstract class

The difference between interface and abstract class

	Abstract class	interface
Keyword	abstract class	interface
inherit	Only one abstract class can be inherited	Multiple interfaces can be implemented
area	Can have instance domain	Must not have instance domains
method	There can be ordinary methods	There can only be static, default abstract methods
Constructor	Can have a constructor	No
purpose	For reuse	Decoupling