what's going wrong in my below writing and reading in ObjectStream

below code to write my objects and byte[] into file with sigBytes being my byte[]

ObjectOutputStream outputOS = new ObjectOutputStream(new FileOutputStream(outputFile));
    outputOS.writeInt(sigBytes.length);
    outputOS.write(sigBytes);
    outputOS.writeObject(text);
    outputOS.close();

then when i execute code below i get an java.io.OptionalDataException

ObjectInputStream inputIS = new ObjectInputStream(new FileInputStream(INPUT));
    int length = inputIS.readInt();
    byte[] sigBytes = new byte[length];
    inputIS.read(sigBytes, 0, length);
    String text = (String) inputIS.readObject();

Below the error I get at String text = (String) inputIS.readObject():

java.io.OptionalDataException at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1305) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371) at encryption3.Encryption3.decrypt(Encryption3.java:34) at encryption3.Encryption3.main(Encryption3.java:53)

EDIT i can't make the error repeat in a minimal as below??? and i'm really to tired for this..

public static void doThings() {

    try {
        File file = new File("C:/edges/input.ext");

        String text = "Hello";
        file.createNewFile();

        byte[] sigBytes = (text).getBytes();

        ObjectOutputStream outputOS = new ObjectOutputStream(new FileOutputStream(file));
        outputOS.writeInt(sigBytes.length);
        outputOS.write(sigBytes);
        outputOS.writeObject(text);

        ObjectInputStream inputIS = new ObjectInputStream(new FileInputStream(file));
        int length = inputIS.readInt();
        byte[] sigBytes2 = new byte[length];
        inputIS.read(sigBytes2, 0, length);
        String text2 = (String) inputIS.readObject();
    } catch (IOException | ClassNotFoundException ex) {
        Logger.getLogger(EncryptionError.class.getName()).log(Level.SEVERE, null, ex);
    }
}