interface in java

1// interface in java example
2interface Vehicle
3{
4   public void accelerate();
5}
6class BMW implements Vehicle
7{
8   public void accelerate()
9   {
10      System.out.println("BMW accelerating...");
11   }
12}
13public class InterfaceDemo
14{
15   public static void main(String[] args)
16   {
17      BMW obj = new BMW();
18      obj.accelerate();
19   }
20}

1// Assume we have the simple interface:
2interface Appendable {
3	void append(string content);
4}
5// We can implement it like that:
6class SimplePrinter implements Appendable {
7 	public void append(string content) {
8   		System.out.println(content); 
9    }
10}
11// ... and maybe like that:
12class FileWriter implements Appendable {
13 	public void append(string content) {
14   		// Appends content into a file 
15    }
16}
17// Both classes are Appendable.

1/* File name : MammalInt.java */
2public class MammalInt implements Animal {
3
4   public void eat() {
5      System.out.println("Mammal eats");
6   }
7
8   public void travel() {
9      System.out.println("Mammal travels");
10   } 
11
12   public int noOfLegs() {
13      return 0;
14   }
15
16   public static void main(String args[]) {
17      MammalInt m = new MammalInt();
18      m.eat();
19      m.travel();
20   }
21} 

1Interfaces specify what a class must do. 
2It is the blueprint of the class.
3It is used to achieve total abstraction. 
4We are using implements keyword for interface.
5
6Basic statement we all know in Selenium is
7WebDriver driver = new FirefoxDriver();
8WebDriver itself is an Interface.
9So we are initializing Firefox browser
10using Selenium WebDriver.
11It means we are creating a reference variable
12of the interface and creating an Object.
13So WebDriver is an Interface and
14FirefoxDriver is a class.
15
16

1/* File name : Animal.java */
2interface Animal {
3   public void eat();
4   public void travel();
5}

1// interface syntax
2interface InterfaceName
3{
4   fields // by default interface fields are public, static final
5   methods // by default interface methods are abstract, public
6}