title: convert 2 Dimensional array String to 2 Dimensional Array Double
body: <p>I have an array that contains number value and a String. I want convert that array into double. I have tried this:</p>
  
  <pre><code>int tableStringLength=tableString.length;
  double [][]tableDouble= null;
  
  for(int i=0; i&lt;tableStringLength; i++) {
      for(int j=0; j&lt;tableStringLength; j++) {
          tableDouble[i][j]= Double.parseDouble(tableString[i][j]);
      }
  }
  </code></pre>
  
  <p>but it returns nothing, not null or zero when I try to display in screen.</p>