500
The problem with the following code, which is supposed to copy arr1 into arr2:
int[][] arr1 = {{1,2,3},{4,5,6}};
int[][] arr2 = new int[arr1.length][];
for (int i = 0; i < arr1.length; i++)
for (int j = 0; j < arr1[i].length; j++)
arr2[i][j] = arr1[i][j];
What is the rows of arr2 have not been initialized?