Java Display File-Extension

In this program you will learn how to display the file extension of the file. Here you will be asked to enter the file name and then you will get the extension of the file.

Description of the code:

In the program code given below, you will be asked to enter the file name first as can be observed from the method of java.io.*; package which is BufferedReader();. The compiler will read the file name once you enter it through readLine(); method. Then we have declared the local variables here filename and extension. Now, to find the position of the last dot we have used a method lastIndexOf(); to get the extension. At the last we have applied show(); method to get the extension.

The code of the program is given below:

import java.io.*; import java.lang.String; public class FileExtension{     public void show(String extension){   System.out.println("Extension is" + " " + extension);   }   public static void main(String args[])throws IOException{   BufferedReader bf =    new BufferedReader(new InputStreamReader(System.in));   System.out.println("Enter the file name:");   String filenameExtension = bf.readLine();   File filename = new File(filenameExtension);   if(!filename.exists())   {   System.out.println("File does not exist.");   System.exit(0);   }   String extension;   int dotPos = filenameExtension.lastIndexOf(".");   extension = filenameExtension.substring(dotPos);   FileExtension abc = new FileExtension();    abc.show(extension);   } }

Output of the program:

C:\unique>javac FileExtension.java C:\unique>java FileExtension Enter the file name: