To reverse an int array, you swap items up until you reach the midpoint, like this:

for(int i = 0; i < validData.length / 2; i++)
{
    int temp = validData[i];
    validData[i] = validData[validData.length - i - 1];
    validData[validData.length - i - 1] = temp;
}

The way you are doing it, you swap each element twice, so the result is the same as the initial list.

You are assigning values from an uninitialized array d to x - that's where the zeroes (default value for an int in Java) are coming from.

IIUC, you're mixing two reversing strategies.

If you're creating a new array, you needn't run over half of the original array, but over all of it:

public static int[] reverse(int[] x) {

    int[] d = new int[x.length];


    for (int i = 0; i < x.length; i++) {
        d[i] = x[x.length - 1 -i];
    }
    return d;
}

Alternatively, if you want to reverse the array in place, you don't need a temp array, only a single variable (at most - there are also ways to switch two ints without an additional variable, but that's a different question):

public static int[] reverseInPlace(int[] x) {
    int tmp;    

    for (int i = 0; i < x.length / 2; i++) {
        tmp = x[i];
        x[i] = x[x.length - 1 - i];
        x[x.length - 1 - i] = tmp;
    }
    return x; // for completeness, not really necessary.
}

Collections.reverse() can do that job for you if you put your numbers in a List of Integers.

List<Integer> list = Arrays.asList(1, 4, 9, 16, 9, 7, 4, 9, 11);
System.out.println(list);
Collections.reverse(list);
System.out.println(list);

Output:

[1, 4, 9, 16, 9, 7, 4, 9, 11]
[11, 9, 4, 7, 9, 16, 9, 4, 1]

If you want to reverse the elements in the array, you need to write method swap() like this:

static void swap(int[] arr) {
    for (int start = 0; start < arr.length / 2; start++) {
        int tmp = arr[arr.length - 1 - start];
        arr[arr.length - 1 - start] = arr[start];
        arr[start] = tmp;
    }
}

Arrays in Java are indexed from 0 to length - 1, not 1 to length, therefore you should be assign your variable accordingly and use the correct comparison operator.

Your loop should look like this:

for (int counter = myArray.length - 1; counter >= 0; counter--) {