Why jFileChosser.getSelectedFile().getAbsolutePath(); is not working in my project?

Question

I am trying to write an excel file in a directory that the user will selected with a JFileChooser which is already working well.

My problem is that, when I am passing the path to a String:

private void JFileChooserExcActionPerformed(java.awt.event.ActionEvent evt) {                                                
    JFileChooserExc.setCurrentDirectory(new java.io.File("."));
    JFileChooserExc.setFileSelectionMode(JFileChooserExc.DIRECTORIES_ONLY);
    JFileChooserExc.setAcceptAllFileFilterUsed(false);

    if (JFileChooserExc.showOpenDialog(this) == JFileChooserExc.APPROVE_OPTION) {
        try {
            String path = JFileChooserExc.getSelectedFile().getAbsolutePath(); //Here is the problem
            Rank(path);
        } catch (IOException ex) {
            Logger.getLogger(Principal.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}

I receive the next exception:

"AWT-EventQueue-0" java.lang.NullPointerException

And the program broke.

I search for many websites and it looks like my code is fine. Any help with be appreciate.