This is the speedy one;

static int[]
array={0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
System.arraycopy(array, 0, myarray, 0, 12);

: )

And this is the Arrays.fill implementation

public static void fill(int[] a, int fromIndex, int toIndex, int val) {
rangeCheck(a.length, fromIndex, toIndex);
for (int i=fromIndex; i<toIndex; i++)
a[i] = val;
}