Miscellany

 you have a 4x4 String[][] with values:


   W   T   Q  U
   I   L   J  A
   O   J   F  S
   L   O   S  Z

The positions of these letters if put into a single array would be:
  
   0   1   2   3 
   4   5   6   7
   8   9   10  11 
   12  13  14  15