Creating multi-dimensional arrays

Examine the following double array:

      double ar[][] = 
        { { 20.0 },
          { 20.0, 19 },
          { 20.0, 19.0, 18.0 },
          { 20.0, 19.0, 18.0, 17.0 },
          { 20.0, 19.0, 18.0, 17.0, 16.0 } };

You can achieve the same setup dynamically by looping through the row indices and dynamically creating a array with variable length:

public class Main {
   public static void main(String []args) {
      double ar[][] = null;
 
      ar = new double[5][];
      for (int i=0; i<ar.length; i++) {
         ar[i] = new double[i+1];
         for (int j=0; j<i+1; j++) {
            ar[i][j] = (double) 20 - j;
         }
      }
 
      for (int i=0; i<ar.length; i++) {
         for (int j=0; j<ar[i].length; j++) {
            System.out.print(ar[i][j] + " ");
         }
         System.out.println();
      }
   }
}