Java doesn't really have two dimensional arrays. Rather, it has arrays of arrays. What that means is, if we assume you mean the first index is the 'number of rows' then the number of 'columns' (the second length of the inner array) can vary from row to row. A common approach to get 'the number of columns' would be to get the length of the array at T[0] (the length of the first array indexed in T).

Mack Grill wrote:
...and what would this expression return for T?