So if you are here it is sure you need a piece of code which could help you to open any external file using java.And this article will tell you how you could do that.

java.awt.Desktop

The Desktop class of awt package allows java programs to launch any  file in its default editor.Means if the file is .txt it might open in Notepad if it is .pdf then it will open in adobe reader and if it is (.html) then it will open in your default web browser.

NOTE:- If we will try to open a file which does not exists then it will throw 

                                          java.lang.IllegalArgumentException

So here is the whole source code

openIt.java 

import java.util.Scanner;
public class OpeIt {

    public static void main(String[] args) throws IOException 
    {
        System.out.print("Enter the path of the file to open");
        String path=sc.nextLine();
        File file = new File(path);
        
        //first check if Desktop is supported by Platform or not
        if(!Desktop.isDesktopSupported())
        {
            System.out.println("Desktop is not supported");
            return;
        }
        
        Desktop desktop = Desktop.getDesktop();
        if(file.exists()) 
        desktop.open(file);
        else
        System.out.println("The file does not exists");
       
    }

}