Error: Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0

Question

I'm new to Java and I'm facing this error when trying to start the application.

My code looks like this:

public class Testen {   
    public static void main( String[] args){ 
        int a = Integer.parseInt(args[0]);

    System.out.println(a);
    }
}

I've already read threads of people who were facing similar errors, however, I'm failing to apply their solutions to my code.

Answer 1

As someone is the comments pointed out, when you run java code from command line like this: java testen arg0 arg1 arg2 arg3, then these arguments are stored inside the the string array String[] args. To access the arg0 you can use args[0] in your code.

If you run java testen then your string array args will be empty, so you can't access an element that doesn't exist, and you get the exception.