HOw to check the extension in java

[supahsain08]

This is what i have to do

Write a program that prompts the user for a file name (including the extension), checks the extension and responds with a comment about the type of file, for example ?

.doc ? That was a Word document!
.xls ? That was an Excel spreadsheet!
.java ? That was a Java source file!


My code so far

code:

import java.util.Scanner; import java.io.*; class string {         public static void main(String[] args) throws Exception         {         Scanner in = new Scanner(System.in);                                 String extension;                 System.out.println ("Please enter a file name with extension.");                                 extension = in.nextLine();                 Scanner s = new Scanner(extension);                 s.findInLine(.doc);                                                                                                   if (s.equals(.doc))                 {                                 System.out.println ("doc file.");                 }                 else                 {                                 System.out.println ("none.");                 }                                 }                 }

I can't seem to figure out, any ideas