J2ME Bouncy Castle get AES encryption result as String

Question

I'm developing some app in J2ME which send and receives encrypted messages, I found the code below to encrypt it and convert to String but it doesn't work and throw exception, how should I do this? and how should I convert String to byte[] when I want to do decryption? thanks

 byte[] plainArray = message.getBytes();
        try {
            byte[] keyBytes = "SECRET_1SECRET_2SECRET_3".getBytes();

            // key = new KeyParameter(keyBytes);
            AESEngine engine = new AESEngine();
            PaddedBufferedBlockCipher cipher = new PaddedBufferedBlockCipher(engine);
            cipher.init(true, new KeyParameter(keyBytes));
            byte[] cipherBytes = new byte[cipher.getOutputSize(plainArray.length)];
            int cipherLength = cipher.processBytes(plainArray, 0, plainArray.length, cipherBytes, 0);
            cipher.doFinal(cipherBytes, cipherLength);

            String result2 = org.apache.commons.codec.binary.Base64.encodeBase64String(cipherBytes);
            formSender.append(result2);

        } catch (Exception e) {
        } 

Exception :

TRACE: , Exception caught in Display class java.lang.Error: ClassFormatError: 56 at SSMS.EncShow(), bci=173 at SSMS.commandAction(), bci=16 at javax.microedition.lcdui.Display$ChameleonTunnel.callScreenListener(), bci=44 at com.sun.midp.chameleon.layers.SoftButtonLayer.processCommand(), bci=80 at com.sun.midp.chameleon.layers.SoftButtonLayer.soft1(), bci=31 at com.sun.midp.chameleon.layers.SoftButtonLayer.keyInput(), bci=48 at com.sun.midp.chameleon.CWindow.keyInput(), bci=38 at javax.microedition.lcdui.Display$DisplayEventConsumerImpl.handleKeyEvent(), bci=32 at com.sun.midp.lcdui.DisplayEventListener.process(), bci=294 at com.sun.midp.events.EventQueue.run(), bci=177 at java.lang.Thread.run(Thread.java:722)

Answer 1

According to http://docs.oracle.com/javase/1.4.2/docs/api/java/lang/ClassFormatError.html "Thrown when the Java Virtual Machine attempts to read a class file and determines that the file is malformed or otherwise cannot be interpreted as a class file".

Your org.apache.commons version might be too new for Java ME, which is based on Java 1.3. Be sure to use older versions of org.apache.commons.