jcryption 3.0 encryption to java decryption

Question

I am trying to use JCrytion 3.0.1 to encrypt data in javascript and then decrypt it on server by java. My question is how I can get the encrypted string to decrypt it in java using Cipher class which requires Byte[] to process.
This is how I generate my key from java

final KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
keyGen.initialize(1024);
final KeyPair key = keyGen.generateKeyPair();

And then to decrypt data I used

public  String decrypt(byte[] text, PrivateKey key) {
    byte[] dectyptedText = null;
    try {
        final Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, key);
        dectyptedText = cipher.doFinal(text); // this is where I get error when trying to use getBytes() to convert encrypted string to byte[]
    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return new String(dectyptedText);
}

This is my javascript on client side

var encryptedUser = $.jCryption.encrypt(username, keys);
var encryptedPassword = $.jCryption.encrypt(password, keys);
            alert("Start Submiting");
            $.ajax({
                url: "LoginAuthentication",
                data:{username:encryptedUser, password:encryptedPassword},
                type:'POST'
            }).done(function(){
                alert("Successfully Access !!!");
            });

I try to use getBytes() but it doesn't work
It works well with other texts I test. My Only problem is how to convert encrypted string from javascript using JCryption to byte[] to decrypt it in Java.
Thank You