What is interface class in java code example

Example 1: Interface in java

// interface in java example
interface Vehicle
{
   public void accelerate();
}
class BMW implements Vehicle
{
   public void accelerate()
   {
      System.out.println("BMW accelerating...");
   }
}
public class InterfaceDemo
{
   public static void main(String[] args)
   {
      BMW obj = new BMW();
      obj.accelerate();
   }
}

Example 2: interface in java

Interfaces specify what a class must do. 
It is the blueprint of the class.
It is used to achieve total abstraction. 
We are using implements keyword for interface.

Basic statement we all know in Selenium is
WebDriver driver = new FirefoxDriver();
WebDriver itself is an Interface.
So we are initializing Firefox browser
using Selenium WebDriver.
It means we are creating a reference variable
of the interface and creating an Object.
So WebDriver is an Interface and
FirefoxDriver is a class.

Example 3: interface in java

/* File name : MammalInt.java */
public class MammalInt implements Animal {

   public void eat() {
      System.out.println("Mammal eats");
   }

   public void travel() {
      System.out.println("Mammal travels");
   } 

   public int noOfLegs() {
      return 0;
   }

   public static void main(String args[]) {
      MammalInt m = new MammalInt();
      m.eat();
      m.travel();
   }
}

Example 4: Interface in java

// interface syntax
interface InterfaceName
{
   fields // by default interface fields are public, static final
   methods // by default interface methods are abstract, public
}

Example 5: interface in java

/* File name : Animal.java */
interface Animal {
   public void eat();
   public void travel();
}