Fields and Methods in an Interface : Interface « Class Definition « Java Tutorial

  1. Fields in an interface must be initialized and are implicitly public, static, and final.
  2. You declare methods in an interface just as you would in a class.
  3. Methods in an interface do not have a body.
  4. All methods are implicitly public and abstract
interface Conversions{
  double inchesToMillimeters(double inches);


5.29.1.Interfaces and Abstract Classes
5.29.2.Fields and Methods in an Interface
5.29.3.To implement an interface: use the implements keyword after the class declaration
5.29.4.A Partial Interface Implementation
5.29.5.Extending Interfaces
5.29.6.Interfaces and Multiple Inheritance
5.29.7.Interfaces and Polymorphism: Using Multiple Interfaces
5.29.8.Nesting Classes in an Interface Definition
5.29.9.Encapsulating Constants in a Program
5.29.10.Multiple interfaces
5.29.11.Initializing interface fields with non-constant initializers