java 2d array hackerrank solution, This example take 6x6 multidimensional array, divides that array into 3x3 matrix. then adds each element to the sum, for a given 6x6 matrix there will be 16 3x3 matrices. Hourglass matrix means its 3x3 matrix,ignoring first row,column 0, then first row column 2 values.
This is an example of how to use 2d matrix in java. In this video not checking all elements are zeros.
