Base64UrlUtil { public static byte[] decode(String source) { return decoder.decode(source); } private  Base64UrlUtil(); static byte[] decode(String source); static byte[] decode(byte[] source); static byte[] encode(byte[] source); static String encodeToString(byte[] source);  }
@Test void decode_test() { byte[] data = new byte[]{0x41, 0x53, 0x4E, 0x46}; byte[] expected = new byte[]{0x01, 0x23, 0x45}; byte[] result = Base64UrlUtil.decode(data); assertThat(result).isEqualTo(expected); }