My Java Chatbot code don't work and i don't know why

Question

I am new to Java and this is part of my chatbot code. When I run createQuestions() from showMenu() it doesn't seem to work. What createQuestion() does is let the user create questions and chat with themselves.

The problem is here

Welcome!

Choose your option:

1) Add Questions

2) Chat(You need to add question first)

3) Know more about Towns

4) Exit

You: 1

Creating questions...Type 'end' if you wish to stop Question? (it doesn't pause here as I need to read what the user input and store it as question)

You:

How many responses do you want? :

        //Start of ShowMenu():
        txtChat.append("\nWelcome!\nChoose your option:");
        txtChat.append("\n1)Add Questions\n2)Chat(You need to add question first)\n3)Know more about Towns\n4)Exit\n");
        txtChat.append(">>>\n");

        txtEnter.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                showMenu();
            }//end actionPerformed

        });//end actionListener

    }//end TestinChatBot

    public void showMenu() {
        String choice;

        do {

            switch (choice) {
                case "1":
                    createQuestions();
                    break;
                case "2":
                    startChat();
                    break;
                case "3":
                    knowtowns();
                    break;
                case "4":
                    txtChat.append("\nFinally! I can play MapleStory! Sayonara!");
                    System.exit(0);
                    break;
                default:
                    break;
            }

        } while (!choice.equals("4"));

    }

    public void createQuestions() {
        txtChat.append("\nCreating questions...Type 'end' if you wish to stop\n");

        do {

            txtChat.append("Question? \n");
            q = txtEnter.getText();
            txtChat.append("You: " + q + "\n");

            if (!q.contains("end")) {
                txtChat.append("How many responses do you want? : ");
                noOfResponses = Integer.parseInt(txtEnter.getText());
                txtEnter.setText("");
                String r[] = new String[noOfResponses];
                if (noOfResponses > 0) {
                    for (int i = 0; i < noOfResponses; i++) {
                        txtChat.append("Response " + (i + 1) + ": ");
                        r[i] = txtEnter.getText();
                        txtEnter.setText("");

                    }
                    Chat newChat = new Chat(q, r);
                    addQuestion(newChat);
                    txtChat.append("\n" + Arrays.toString(r));
                } else {
                    txtChat.append("Please enter a number bigger than 0");

                }
            } else {
                showMenu();
            }
        } while (q.equalsIgnoreCase("end") == false);
    }

and the errors are these

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: ""

Answer 1

If txtEnter.getText() returns blank you get:

 java.lang.NumberFormatException: For input string: ""

because blank can not be converted to a number.

So you should check to make sure that txtEnter.getText() does not return blank.