interface keyword in java
The ” interface ” keyword is used to declare a new Java interface, which is a collection of methods and constants.
Interfaces are a powerful feature of the Java language.
Any class can implement one or more interfaces, meaning it implements all of the methods declared in those interfaces.
Example
- interface Shape{
- public double getArea();
- public void draw();
- }
interface Shape{
public double getArea();
public void draw();
}
Now any number of classes can implement this interface as we can see below that Triangle class is implementing it
- Class Triangle implements Shape{
- double base=5;
- double height=10;
- public double getArea(){
- return 0.5*base*height;
- }
- public void draw(){
- System.out.println("It's a triangle");
- }
- }
Class Triangle implements Shape{
double base=5;
double height=10;
public double getArea(){
return 0.5*base*height;
}
public void draw(){
System.out.println("It's a triangle");
}
}
Note:
All the methods in the interface are public and abstract
All the constants defined in the interface are public,static and final
