NullPointerException in JFileChooser.showOpenDialog() JRE 1.7

Question

Hi all,
In my application, i have used JFileChooser to select a file. When i try to open JFileChooser.showOpenDialog() it throws the following exception. Not sure where i am wrong. Please help me.
Exception:
#Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
# at sun.awt.shell.Win32ShellFolder2.access$200(Unknown Source)
# at sun.awt.shell.Win32ShellFolder2$1.call(Unknown Source)
# at sun.awt.shell.Win32ShellFolder2$1.call(Unknown Source)
# at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
# at java.util.concurrent.FutureTask.run(Unknown Source)
# at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
# at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
# at sun.awt.shell.Win32ShellFolderManager2$ComInvoker$3.run(Unknown Source)
# at java.lang.Thread.run(Unknown Source)
Source Code:
     public File browseFile() {
          UIManager.put("FileChooser.readOnly", Boolean.TRUE);
          if (DEBUG > 4) {
               System.out.println("Initial Dir : " + initialDir);
               System.out.println("Title : " + title);
          JFileChooser jfc = new JFileChooser();
          FileFilter filter = null;
          if (null != extension && extension.trim().length() > 0) {
               if (null != description && description.trim().length() > 0) {
                    filter = new ExtensionFilter(this.description, this.extension);
               } else {
                    filter = new ExtensionFilter(this.extension, this.extension);
               jfc.setFileFilter(filter);
          if (null != title && title.trim().length() > 0) {
               jfc.setDialogTitle(title);
          if (null != initialDir) {
               jfc.setCurrentDirectory(new File(initialDir));
          int returnVal = - 1;
          if (type == JFileChooser.OPEN_DIALOG) {
               returnVal = jfc.showOpenDialog(this);
          } else if (type == JFileChooser.SAVE_DIALOG) {
               returnVal = jfc.showSaveDialog(this);
          if (returnVal == JFileChooser.APPROVE_OPTION) {
               File file = jfc.getSelectedFile();
               setVisible(false);
               return file;
          } else {
               setVisible(false);
               return null;
Thanks for all in Advance.
/dhavan

Answer 1

Sorry, actually i commented that line. Here is the updated code.
     public File browseFile() {
          parent = this;
          UIManager.put("FileChooser.readOnly", Boolean.TRUE);
//          if (DEBUG > 4) {
               System.out.println("Initial Dir : " + initialDir);
               System.out.println("Initial File : " + initialFile);
               System.out.println("Title : " + title);
          try {
               EventQueue.invokeLater( new Runnable() {
                    public void run() {
                         jfc = new JFileChooser();
                         FileFilter filter = null;
                         if (null != extension && extension.trim().length() > 0) {
                              if (null != description && description.trim().length() > 0) {
                                   filter = new ExtensionFilter(description, extension);
                              } else {
                                   filter = new ExtensionFilter(extension, extension);
                              jfc.setFileFilter(filter);
                         if (null != title && title.trim().length() > 0) {
                              jfc.setDialogTitle(title);
                         if (null != initialDir) {
                              jfc.setCurrentDirectory(new File(initialDir));
                    if (type == JFileChooser.OPEN_DIALOG) {
                         System.out.println("JFileChooser.OPEN_DIALOG");
                         returnVal = jfc.showOpenDialog(parent);
                    } else if (type == JFileChooser.SAVE_DIALOG) {
                         System.out.println("JFileChooser.SAVE_DIALOG");
                         returnVal = jfc.showSaveDialog(parent);
          } catch (Exception ex) {
               ex.printStackTrace();
          return null;
          if (returnVal == JFileChooser.APPROVE_OPTION) {
               File file = jfc.getSelectedFile();
               return file;
          } else {
               return null;
     }Exception:-
#Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
#     at sun.awt.shell.Win32ShellFolderManager2.createShellFolder(Unknown Source)
#     at sun.awt.shell.Win32ShellFolderManager2.getRecent(Unknown Source)
#     at sun.awt.shell.Win32ShellFolderManager2.get(Unknown Source)
#     at sun.awt.shell.ShellFolder.get(Unknown Source)
#     at sun.swing.WindowsPlacesBar.<init>(Unknown Source)
#     at com.sun.java.swing.plaf.windows.WindowsFileChooserUI.updateUseShellFolder(Unknown Source)
#     at com.sun.java.swing.plaf.windows.WindowsFileChooserUI.installComponents(Unknown Source)
#     at javax.swing.plaf.basic.BasicFileChooserUI.installUI(Unknown Source)
#     at com.sun.java.swing.plaf.windows.WindowsFileChooserUI.installUI(Unknown Source)
#     at javax.swing.JComponent.setUI(Unknown Source)
#     at javax.swing.JFileChooser.updateUI(Unknown Source)
#     at javax.swing.JFileChooser.setup(Unknown Source)
#     at javax.swing.JFileChooser.<init>(Unknown Source)
#     at javax.swing.JFileChooser.<init>(Unknown Source)
#     at com.marimba.ncp.apps.editor.SwingFileChooser$1.run(SwingFileChooser.java:59)
#     at java.awt.event.InvocationEvent.dispatch(Unknown Source)
#     at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
#     at java.awt.EventQueue.access$000(Unknown Source)
#     at java.awt.EventQueue$1.run(Unknown Source)
#     at java.awt.EventQueue$1.run(Unknown Source)
#     at java.security.AccessController.doPrivileged(Native Method)
#     at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
#     at java.awt.EventQueue.dispatchEvent(Unknown Source)
#     at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
#     at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
#     at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
#     at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
#     at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
#     at java.awt.EventDispatchThread.run(Unknown Source)