Recieving Error from decryption with RSA

I'm doing a small school "project" that is a small chat program. You start the server and the server sends a public key to the client so that the client can send back encrypted data.

The problem is that when I try to decrypt it on the server side I recieve a error.

javax.crypto.BadPaddingException: Decryption error
at sun.security.rsa.RSAPadding.unpadV15(RSAPadding.java:380)
at sun.security.rsa.RSAPadding.unpad(RSAPadding.java:291)

My server awaits for a socket.accept() and when a client connect it sends a public key to this socket.

(This is not the whole code)

private Client client;
private JSONObject json;

//Connector is used as a listener for messages.
public Connector(Socket socket, ServerBroadCast SBC) throws IOException {
    DIS = new DataInputStream(socket.getInputStream());        
    this.SBC = SBC;
    this.client = SBC.AddClient(socket);        
    //Sending public RSA key to client to use to encrypt their message
    this.client.sendPublicKey(RSA.getPublicKey()); //This is where I am sending RSA public key to client
}

I'm just sending one message back to server to see if it's encrypted and if the server can decrypt it.

Using this class to send to CLIENT

DataOutputStream DOS;
public Client(Socket s) throws IOException {
    DOS = new DataOutputStream(s.getOutputStream());
}
public void sendPublicKey(PublicKey publicKey) throws IOException {
    JSONObject json = new JSONObject();

    json.put(JSONKeys.TYPE, JSONTypes.PUBLIC_KEY);
    json.put(JSONKeys.MESSAGE, RSA.getEncodedPublicKey());
    this.send(json);
}

public void send(JSONObject json) throws IOException{
    this.DOS.writeUTF(json.toString());
    System.out.println(json);
}

And here is my RSA class to encrypt and decrypt

private static PrivateKey privateKey = null;
private static PublicKey publicKey = null;

public static void generateKeyPair() {
    KeyPairGenerator keyPairGenerator = null;
    KeyPair keyPair = null;

    try {
        keyPairGenerator = KeyPairGenerator.getInstance("RSA");
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    }

    keyPairGenerator.initialize(1024);
    keyPair = keyPairGenerator.generateKeyPair();

    RSA.privateKey = keyPair.getPrivate();
    RSA.publicKey = keyPair.getPublic();
}

public static String getEncodedPublicKey() {
    return (new String(Base64.encode(RSA.getPublicKey().getEncoded())));
}

public static String encrypt(String string) {
    byte[] encrypted = null;

    try {
        Cipher cipher = Cipher.getInstance("RSA");//174 bytes

        cipher.init(Cipher.ENCRYPT_MODE, RSA.getPublicKey());
        encrypted = cipher.doFinal(string.getBytes());
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    } catch (NoSuchPaddingException e) {
        e.printStackTrace();
    } catch (InvalidKeyException e) {
        e.printStackTrace();
    } catch (IllegalBlockSizeException e) {
        e.printStackTrace();
    } catch (BadPaddingException e) {
        e.printStackTrace();
    }

    return (new String(Base64.encode(encrypted)));
}

public static String decrypt(String string) {
    byte[] decrypted = null;

    try {
        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");

        cipher.init(Cipher.DECRYPT_MODE, RSA.getPrivateKey());
        decrypted = cipher.doFinal(Base64.decode(string));
    } catch (InvalidKeyException e) {
        e.printStackTrace();
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    } catch (NoSuchPaddingException e) {
        e.printStackTrace();
    } catch (IllegalBlockSizeException e) {
        e.printStackTrace();
    } catch (BadPaddingException e) {
        e.printStackTrace();
    } catch (Base64DecodingException e) {
        e.printStackTrace();
    }

    return (new String(decrypted));
}

I get that there is something "wrong" with my padding since the error says that but I don't understand what.

The length of what I get back from the clients encrypted message is 174 byte long. I've understood that it is to long, but why does it create such a huge encrypted message from my plain text.

private final String MESSAGE = "Hello from client side";