Question

Why am I getting java.lang.ArrayIndexOutOfBoundsException :0 at CopyFile.main

//Copy one file Data to another File
import java.io.*;

class CopyFile{

        public static void main(String[] args)throws IOException{
            FileInputStream fis=new FileInputStream(args[0]);//reading File 
            FileOutputStream fos=new FileOutputStream(args[1]);//reading File
            int data;

            while((data=fis.read())!=-1){
                fos.write(data);
/*here  using while loop to copy data from one file and storing it in another file*/
            }
        }
}

Answer 1

It seems you are running the file as

java CopyFile

If you do so, its wrong. You should pass the arguments to run your code since your are looking for two arguments.

Run the code this way:-

java CopyFile arg1 arg2