### Question:
Base64 { public static boolean isBase64(byte octet) { return octet == PAD || (octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1); } Base64(); static boolean isBase64(byte octet); static String encodeBase64String(byte[] binaryData); static byte[] encodeBase64(byte[] binaryData); static byte[] decodeBase64(String base64String); static byte[] decodeBase64(byte[] base64Data); byte[] decode(String pArray); byte[] decode(byte[] pArray); byte[] encode(byte[] pArray);  }### Answer:
@Test public void testIsBase64() { assertTrue(Base64.isBase64((byte) 'b')); assertFalse(Base64.isBase64((byte) ' ')); }