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When I process a large volume of data during encryption its heap size becomes full and throws java.lang.OutOfMemoryError

I don't want to increase the java heap size manually in my container

Here is my java code

public String encrypt(String data) {
        try {
            IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
            SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), "AES");

            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);

            byte[] encrypted = cipher.doFinal(data.getBytes());
            return Base64.encodeBase64String(encrypted);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return null;
    }

I also heard to use cipher.update first then use cipher.doFinal but it won't work for me because i am dealing with only single block of data

What do I do so that my heap size does not affect?

I saw similar issue Java Out of Memory Error during Encryption but it won't resolve my problem

I also don't want to specify the maximum amount of bytes to proceed at time

UDIT JOSHI
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  • You are probably processing large `data` input. Which you have at least 3 times in memory. A copy in `encrypted` and then an even larger `String` in `Base64.encodeBase64String`. Al that is in memory and will use up space. – M. Deinum Dec 17 '19 at 11:10

1 Answers1

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Use a CipherOutputStream:

CipherOutputStream cos = new CipherOutputStream( new FileOutputStream("ciphertext"), cipher);

Now write to the stream using any mechanism including Writer. 

PrintWriter pw = new PrintWriter(new OutputStreamWriter(cos));
pw.println(data);

Don’t forget to close any streams when done.

Strelok
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