java: JOptionPane.showInputDialog null pointer exception

Question

    String response = javax.swing.JOptionPane.showInputDialog("Enter new database name:");

This throws a null pointer error if the user x's out of the optionpane

Firstly, why can't response hold a null value?

secondly, how do i handle this?

full code:

    String response = javax.swing.JOptionPane.showInputDialog("Enter new database name:").trim() + ".xml"; 
    if(response != null){
        File newData = new File("src\\golfdatabase\\Databases\\" + response);
        try {
            newData.createNewFile();
            databaseComboBox.addItem(response);
        } catch (IOException ex) {
            Logger.getLogger(GolfDriver.class.getName()).log(Level.SEVERE, null, ex);
        }
        databaseComboBox.setSelectedItem(response);
        disableButtonsNullList(false);
    }

Answer 1

You have to check the return value for null and then invoke the method trim

String response = javax.swing.JOptionPane.showInputDialog("Enter new database name:");
if(response!=null)
response = response.trim()+".xml";

Answer 2

It gives null back when you click on "Cancel" try something like that:

 String response = javax.swing.JOptionPane.showInputDialog("Enter new database name:");
    if(response != null){
        response = response.trim() + ".xml";
    }

Answer 3

Take note that: String response = JOptionPane.showInputDialog(....); Would have been enough to create the JOptionPane.

Firstly: Yes responses CAN hold a null value, but your code snippet does not show how you handle the responses so there is no way for me to tell why it is throwing them.

Secondly: That again depends on how you are handling the responses, please elaborate more on your code.

EDIT: try adding a String cast as the java tutorial suggests you do: http://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html

EDIT2: While Octopus found the problem in a piece of code (that I shamefully overlooked) please keep in mind the above points because they still hold true.