ADDITIONAL SYSTEM INFORMATION :
OS: macOS 10.14.4
JDK: openjdk-12.0.2

A DESCRIPTION OF THE PROBLEM :
When you abort the creation of a new folder with the "esc" key, a new folder named "uninitializedValue" is created.

I first run into this issue on openjdk-11.0.1. Could reproduce it on openjdk-12.0.2.



STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Open an instance of JFileChooser.
2. Navigate to a directory of your choice (e. g. "~/Desktop").
3. Click on "New folder".
4. Hit the "esc" key to close the "New folder" dialog.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Hitting the "esc" key is equivalently to pressing the "Cancel" button, i. e. no new folder is created when the "New folder" dialog is closed.
ACTUAL -
The directory to which you had last navigated with the JFileChooser before hitting "esc" now contains a directory named "uninitializedValue" (e. g. "~/Desktop/uninitializedValue"). The JFileChooser has navigated into this new folder.

If you continue the reproduction steps, you end up with multiple folders named "uninitializedValue" which are recursively nested into each other.

---------- BEGIN SOURCE ----------
public class Debugging_JFileChooserOnMac {

  public static void main(String[] args) {
    final JFrame frame = new JFrame();

    final JFileChooser fileChooser = new JFileChooser();

    final JButton fileChooserButton = new JButton("Save a file...");
    fileChooserButton.addActionListener(event -> {
      fileChooser.showSaveDialog(frame);
      System.out.println(fileChooser.getSelectedFile());
    });

    frame.add(fileChooserButton);

    frame.setSize(600, 400);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}
---------- END SOURCE ----------