Beware of the default IV blog post example

explicit_iv.java

public byte[] encrypt(byte[] in)
{
    ...
    byte[] iv = new byte[IV_LENGTH];
    new SecureRandom().nextBytes(iv);
    cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(iv));
    byte[] cipherBytes = cipher.doFinal(s.getBytes("UTF-8"));
    return concat(iv, cipherBytes);
}

public byte[] decrypt(byte[] in) throws SecurityException
{
    ...
    cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(bytes, 0, IV_LENGTH));
    return new cipher.doFinal(bytes, IV_LENGTH, bytes.length-IV_LENGTH);
}

secret_key_iv.java

byte[] key = new byte[16];
new SecureRandom().nextBytes(key);
SecretKeySpec keySpec = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding", "AndroidOpenSSL");
cipher.init(Cipher.ENCRYPT_MODE, keySpec);
byte[] cipherBytes = cipher.doFinal(s.getBytes("UTF-8"));
byte[] iv = cipher.getIV();