byte[] to String returns different String

For a given byte[], always the same, I'd like to get the corresponding String. the byte[] result has always the same value.

However the String returned is never the same, each time I launch my app the result changes.

byte[] results = cipher.doFinal(text.getBytes("UTF-8"));

String result = Base64.encodeBase64String(results);

I tried several other ways to get my String like String result = new String(results, "UTF-8");, with Array,... but it remains different everytime.

This is happening after a cipher encryption. Here is the full code:

Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5padding");
byte[] keyBuf= new byte[16];

byte[] b= key.getBytes("UTF-8");
int len= b.length;
if (len > keyBuf.length) len = keyBuf.length;

System.arraycopy(b, 0, keyBuf, 0, len);
SecretKeySpec keySpec = new SecretKeySpec(keyBuf, "AES256");


byte[] ivBuf= new byte[16];
            //IvParameterSpec ivSpec = new IvParameterSpec(ivBuf);
IvParameterSpec ivSpec=null; 

cipher.init(Cipher.ENCRYPT_MODE, keySpec);

byte[] results = cipher.doFinal(text.getBytes("UTF-8"));

String result = Base64.encodeBase64String(results);
return result;

How can I ensure that the String "result" will remains the same?