group values in normal array and move to multidimensional array

I'm struggling to create multi dimensional array by grouping the arrayValues[] in groups of 8 and copying them to the dimensional array. Any help will be appreciated. The code does not give me the right output.

arrayValues = new int[] { 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3 };
int[][] groupedValues =  new int[3][8];
		
for (int a = 0; a < arrayValues.length; a++) {
	groupedValues[0][a] = arrayValues[a];
}
for (int b = 8; b < arrayValues.length; b++) {
	groupedValues[1][b] = arrayValues[b];
}
for (int c = 16; c < arrayValues.length; c++) {
	groupedValues[2][c] = arrayValues[c];
}

The result should be:

groupedValues = [[1, 1, 1, 1, 1, 1, 1, 1], [2, 2, 2, 2, 2, 2, 2, 2], [3, 3, 3, 3, 3, 3, 3, 3]]

But it gives the output:

groupedValues = [[1, 1, 1, 1, 1, 1, 1, 1], [0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0]]

For some reason it doesn't group the next values and add them to the groupedValues[] array.

As already stated in the comments, your code should have surely given you an IndexOutOfBoundsException when adding the values to the array.
This is because you iterate over the complete input array in all three loops and trying to fit 24 values into an sub array of size 8.

This code should work for you:

public static void main(String[] args) {
    int[] arrayValues = new int[] { 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3 };
    int[][] groupedValues = new int[arrayValues.length / 8][8];

    for (int i = 0; i < arrayValues.length / 8; i++) {
        for (int a = 0; a < 8; a++) {
            groupedValues[i][a] = arrayValues[(i * 8) + a];
        }
    }
    System.out.println(Arrays.deepToString(groupedValues));
}

Edit:

In case your input array is not splittable into groups of 8, this should work:

public static void main(String[] args) {
    int[] arrayValues = new int[] { 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3 };
    // Calculate how many groups of 8 there should be available
    int groupSize = (int) Math.ceil(arrayValues.length / 8.0); 
    int[][] groupedValues = new int[groupSize][8];
    int index;

    for (int i = 0; i < groupSize; i++) {
        for (int a = 0; a < 8; a++) {
            index = (i * 8) + a;
            // if the current index is beyond the input array, add 0
            if (index > (arrayValues.length - 1)) {
                groupedValues[i][a] = 0;
            } else {
                groupedValues[i][a] = arrayValues[(i * 8) + a];
            }
        }
    }
    System.out.println(Arrays.deepToString(groupedValues));
}