Java how do I print "empty line" when I come across an empty line on a file of numbers

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Java

file

I have a txt file with 4 by 3 rows and columns of numbers but there is some empty lines (space) in some places, and I am supposed to print the average of each row and column (which I already did) but when I come across an empty line I have to print "empty line" instead.

example:
grid txt file:
40 33 23

20 12 89

22 15 17
78 36 76

output:
average:
200
empty line
222
empty line
120
390

What I have tried:

for (int i = 1; i <= rows; i++){
               for (int j = 1; j <= col; j++){

                   String line = scan.nextLine();
                   while (!line.equals(null)){
                       if (line.equals(" ")){
                           System.out.println("empty line");
                       }

                       double value = scan.nextDouble();

                   switch (c){
                       case 1:
                           col1+=value;
                           break;
                       case 2:
                           col2+=value;
                           break;

                       case 3:
                           col3+=value;
                           break;
                   }
                   switch(r){
                       case 1:
                           row1 += value;
                           break;
                       case 2:
                           row2 += value;
                           break;
                       case 3:
                           row3 += value;
                           break;
                       case 4:
                           row4 += value;
                           break;
                       case 5:
                           row5 += value;
                           break;
                       case 6:
                           row6 += value;
                           break;
                       case 7:
                           row7+= value;
                           break;

                   }


                   }// while
               }

           }