public static byte[] getMacAddress(byte[] linkLocalAddress) {
        return !isLinkLocalAddress(linkLocalAddress) ? null : new byte[] {
                (byte) (linkLocalAddress[8] ^ (1 << 1)),
                linkLocalAddress[9],
                linkLocalAddress[10],
                linkLocalAddress[13],
                linkLocalAddress[14],
                linkLocalAddress[15],
        };
    }
@Test
    public void testMacAddress() {
        assertArrayEquals(getMacAddress(LINK_LOCAL_ADDRESS_1), MAC_ADDRESS_1);
        assertArrayEquals(getMacAddress(LINK_LOCAL_ADDRESS_2), MAC_ADDRESS_2);
    }