title: how fill a 2d array with random strings
body: <p>As the title say i want to populate a 2d array with random strings, in this case "_" and "W", and i made both the 2d array and a random string generator but i can find a away to populate the array created with the string generated</p>
  
  <pre><code>import java.security.SecureRandom;
  
  public class Array_Generator {
  public static void main(String[] args) {
  
      int row = 5;
      int col = 5;
      int[][] grid = new int[row][col];
      String AB = "_W";
      SecureRandom rnd = new SecureRandom();
      for( int i = 0; i &lt; grid.length; i++ ) {
          StringBuilder sb = new StringBuilder(row);
          sb.append( AB.charAt( rnd.nextInt(AB.length()) ) );
          sb.toString();
  
  
      }
  System.out.println(sb);
  </code></pre>
  
  <p>If i do this i get the row like i want, but i cant find a away to do the next ones.</p>
  
  <p>Any help would be apreciated.</p>