The problem is in your switching algorithm. You are assigning temp twice.
int temp = Bub[x];
Bub[x] = Bub[x+1];
temp = Bub[x+1]; //Here should assign Bub[x+1] to temp
//Example: Bub[x+1] = temp
edit-Actually, there could be some improvement in the sorting algorithm itself, too. Personally, I like to do it this way:
public class Sort {
private static int[] array = { 3, 8, -1, 7, 0, 3 };
public static void main(String[] args) {
for(int i = 0; i < array.length - 1; i++) {
for(int j = i + 1; j < array.length; j++) {
if(array[i] > array[j]) {
int temp = array[i];
array[i] = array[j];
array[j] = temp;
}
}
}
for(int i = 0; i < array.length; i++) {
System.out.println(array[i]);
}
}
}