how to find subarray from given large 2d array of arbritary dimension

my code is: import java.lang.*; import java.io.*; import java.io.File; import java.io.IOException; import java.util.ArrayList; import java.util.List; import java.util.Scanner; public class SubMatrix { public static void main(String[] args) throws IOException {

    File file = new File("file1.txt");
    List<float[]> list = new ArrayList<float[]>();
   Scanner scanner = new Scanner(file).useDelimiter("\n");



    while (scanner.hasNext()) {     
        String[] values = scanner.next().trim().split(" "); 
         float[] floats = new float[values.length];
         for (int i = 0; i < values.length; i++) {
             floats[i] = Float.parseFloat(values[i]);
             }
             list.add(floats);
             } 
             float[][] values = new float[list.size()][];
             for (int i = 0; i < list.size(); i++) {
                 values[i] = list.get(i);
                 for (int j = 0; j < values[i].length; j++) {
                     System.out.print(values[i][j] + " ");

                     }
                     System.out.println();
             }


              int row =values.length;
             int col=values[0].length;

//*******************************

              int subrow;
          BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
          System.out.print("Enter the number for rows :");
            subrow = Integer.parseInt(br.readLine());


             double subArray[][] = new double[subrow][col];

             for(int k=0;k<subrow;k++){
                 for(int p=0;p<col;p++){

             System.arraycopy(values,0,subArray,0,subrow);
             System.out.print(subArray[k][p] + " ");
                 }
                 System.out.println();
             }


}}

and .txt file is: 1.0 3.1 2.1 3.4
2.4 2.0 4.6 5.1
0.2 3.3 4.7 9.1
4.0 5.4 5.1 3.2
6.1 2.1 6.4 2.6
1.2 2.0 3.5 6.9
3.1 2.5 4.6 9.8
7.1 8.1 9.4 5.1
12.1 3.1 2.5 2.4
3.8 9.1 2.1 6.7

i want to print the subarray of any dimension from given array file. i have tried upto above code but it gives runtime error as: NumberFormatException:empty string. error might be on "floats[i] = Float.parseFloat(values[i]); " line.help wud be apprec.