public static String s4(int v) {
        char[] result = new char[9];

        if (v < 0) {
            result[0] = '-';
            v = -v;
        } else {
            result[0] = '+';
        }

        for (int i = 0; i < 8; i++) {
            result[8 - i] = Character.forDigit(v & 0x0f, 16);
            v >>= 4;
        }

        return new String(result);
    }
@Test
    public void testS4() {
        Assert.assertEquals("+00000000", Hex.s4(0));
        Assert.assertEquals("-80000000", Hex.s4(-2147483648));
        Assert.assertEquals("+075bcd15", Hex.s4(123456789));
        Assert.assertEquals("+499602d2", Hex.s4(1234567890));
    }