Two dimensional array initializer followed by square brackets

What you are doing here is:

1. Declaring a new variable int[] it (which is a one-dimensional array)
2. Assigning its value from the first element [0]
3. of the two-dimensional array new int[][]
4. which is initialized to be {{1}}

So you create a two-dimensional array which you initialize to contain an array which contains 1 and at the same time you take the first element of the outer array (which is a one-dimensional array containing 1) and assign it to your variable.