Java program just shows Index 0 out of bounds for length 0

I'm doing the askii 2 problem with java, however after my code is done it just shows "Index 0 out of bounds for length 0". this is my code:`

package alex;

import java.io.FileReader;
import java.util.Scanner;

public class askii {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        try {
            FileReader fr=new FileReader("aart.txt");
            Scanner sc= new Scanner(fr);
            String liness=sc.nextLine();
            int lines = Integer.parseInt(liness);
            for (int i=0;i<lines;i++) { 
                String[] num1=sc.nextLine().split(" ");
                int[] num={};
                for(int j=0;j<num1.length;j++) {
                    num[j]=Integer.parseInt(num1[j]);
                }
                for(int j=0;j<num.length;j++) {
                    if(num[j]<53) {
                        if(num[j]%2==0) {
                            int askii =num[j]/2+96;
                            System.out.print(Character.toString(askii));
                        }
                        else {
                            int askii =(int) Math.ceil(num[j]/2)+64;
                            System.out.print(Character.toString(askii));
                        }
                    }
                    else {
                        switch(num[j]){
                        case 53:
                            System.out.print(" ");
                            break;
                        case 54:
                            System.out.print(".");
                            break;
                        case 55:
                            System.out.print(":");
                            break;
                        case 56:
                            System.out.print("*");
                            break;
                        }
                    }
                System.out.println();
                }
            }
                
                
        }
        catch(Exception e){
            System.out.println(e.getMessage());
        }
    }

}

the "aart.txt" is below:

8
53 53 54 38 38 37 38 38 54 53 54 38 38 37 38 38 54
54 38 37 37 37 30 30 37 37 54 37 37 30 30 37 37 37 38 54
54 38 37 30 30 30 30 30 30 30 30 30 30 30 30 30 37 38 54
54 38 37 53 17 53 23 30 44 10 53 49 30 42 53 53 37 38 54
53 53 54 38 37 30 30 30 30 30 30 30 30 30 37 38 54
53 53 53 54 38 37 37 30 30 30 30 30 37 37 38 54
53 53 53 53 53 54 38 37 30 30 30 37 38 54
53 53 53 53 53 53 53 53 54 38 54

this should be the actual output However, in the console it only shows "Index 0 out of bounds for length 0".

Is there anyway to solve this ?

Thanks!