Java: Declaring a multidimensional array without specifying the size of the array ( eg. new int[10][] )

Question

I\'ve been trying to figure out what exactly is happening here. I\'m just trying to figure out what the 2 lines are doing that I\'ve commented on below. I found this program

Answer 1

All new int[10][] is declaring is an array of size 10, containing null arrays.

In the for loop, the null arrays are being instantiated into ever increasing array sizes.