The thing is an Integer is an Object, and a 2D array of Integers taken as a whole is also an Object, just a different kind. You have to decide if you want the elements of the list to be the individual Integers in your array (in your case this is 90 elements), or do you want the elements to be the whole array, so the list only has one element. In the first case, you'd want loops to populate the list, but in the second, you wouldn't. Which form you use depends on your assignment, or in the real word, whichever form will be more useful to the rest of your application.
Printing out a 2D array is going to give you something like: [[Ljava.lang.Integer;@1c78e57 That's probably not what you want, so you will likely need loops to print it out in the form you prefer.