java define interface

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