NullPointerException when using JFileChooser and Java 1.4.0
Thomas Hacklaender
I have a problem when using a JFileChooser and Java 1.4.0 on a Windows
2000 Professional system.
For example, if running NetBeans 3.3.1 and selecting the menu File>Mount
Filesystem...>Local Directory I get the error message:
java.lang.NullPointerException
at java.io.File.<init>(File.java:180)
at
sun.awt.shell.Win32ShellFolder.listFiles(Win32ShellFolder.java:517)
at
sun.awt.shell.Win32ShellFolderManager.get(Win32ShellFolderManager.java:160)
at sun.awt.shell.ShellFolder.get(ShellFolder.java:208)
at
javax.swing.plaf.metal.MetalFileChooserUI.installComponents(MetalFileChooserUI.java:310)
at
javax.swing.plaf.basic.BasicFileChooserUI.installUI(BasicFileChooserUI.java:130)
at
javax.swing.plaf.metal.MetalFileChooserUI.installUI(MetalFileChooserUI.java:152)
at javax.swing.JComponent.setUI(JComponent.java:445)
at javax.swing.JFileChooser.updateUI(JFileChooser.java:1701)
at javax.swing.JFileChooser.setup(JFileChooser.java:345)
at javax.swing.JFileChooser.<init>(JFileChooser.java:320)
at javax.swing.JFileChooser.<init>(JFileChooser.java:273)
at
org.netbeans.beaninfo.editors.FileEditor.createHackedFileChooser(FileEditor.java:355)
at
org.netbeans.beaninfo.editors.FileArrayEditor.getCustomEditor(FileArrayEditor.java:172)
at
org.openide.explorer.propertysheet.PropertyPanel.reset(PropertyPanel.java:649)
at
org.openide.explorer.propertysheet.PropertyPanel.<init>(PropertyPanel.java:259)
at
org.netbeans.core.ui.MountIterator.getComponent(MountIterator.java:237)
at
org.openide.WizardDescriptor.updateState(WizardDescriptor.java:475)
at
org.openide.loaders.TemplateWizard.updateState(TemplateWizard.java:632)
at
org.openide.WizardDescriptor$Listener.stateChanged(WizardDescriptor.java:941)
at
org.openide.loaders.TemplateWizardIterImpl.fireStateChanged(TemplateWizardIterImpl.java:198)
at
org.openide.loaders.TemplateWizardIterImpl.setIterator(TemplateWizardIterImpl.java:70)
at
org.openide.loaders.TemplateWizard.setTemplateImpl(TemplateWizard.java:198)
at
org.openide.loaders.TemplateWizard.setTemplate(TemplateWizard.java:215)
at
org.openide.loaders.TemplateWizard.instantiateImpl(TemplateWizard.java:460)
at
org.openide.loaders.TemplateWizard.instantiate(TemplateWizard.java:426)
at
org.openide.actions.NewTemplateAction$TemplateActionListener.acceptNodes(NewTemplateAction.java:257)
at
org.openide.explorer.view.MenuView$MenuItem.doClick(MenuView.java:504)
at
javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1092)
[catch] at
javax.swing.plaf.basic.BasicMenuItemUI$MouseInputHandler.mouseReleased(BasicMenuItemUI.java:932)
at java.awt.Component.processMouseEvent(Component.java:5021)
at java.awt.Component.processEvent(Component.java:4818)
at java.awt.Container.processEvent(Container.java:1380)
at java.awt.Component.dispatchEventImpl(Component.java:3526)
at java.awt.Container.dispatchEventImpl(Container.java:1437)
at java.awt.Component.dispatchEvent(Component.java:3367)
at
java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3214)
at
java.awt.LightweightDispatcher.processMouseEvent(Container.java:2929)
at
java.awt.LightweightDispatcher.dispatchEvent(Container.java:2859)
at java.awt.Container.dispatchEventImpl(Container.java:1423)
at java.awt.Window.dispatchEventImpl(Window.java:1566)
at java.awt.Component.dispatchEvent(Component.java:3367)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:445)
at
java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:190)
at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:144)
at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:130)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:98)
Another example is a ImageJ plugin which tries to open a file using a
JFileChooser. In this case a get a similar error:
java.lang.NullPointerException
at java.io.File.<init>(File.java:180)
at sun.awt.shell.Win32ShellFolder.listFiles(Win32ShellFolder.java:517)
at
sun.awt.shell.Win32ShellFolderManager.get(Win32ShellFolderManager.java:160)
at sun.awt.shell.ShellFolder.get(ShellFolder.java:208)
at
com.sun.java.swing.plaf.windows.WindowsFileChooserUI.installComponents(WindowsFileChooserUI.java:348)
at
javax.swing.plaf.basic.BasicFileChooserUI.installUI(BasicFileChooserUI.java:130)
at
com.sun.java.swing.plaf.windows.WindowsFileChooserUI.installUI(WindowsFileChooserUI.java:175)
at javax.swing.JComponent.setUI(JComponent.java:445)
at javax.swing.JFileChooser.updateUI(JFileChooser.java:1701)
at javax.swing.JFileChooser.setup(JFileChooser.java:345)
at javax.swing.JFileChooser.<init>(JFileChooser.java:320)
at javax.swing.JFileChooser.<init>(JFileChooser.java:273)
at DICOM_dumpFile.run(DICOM_dumpFile.java:101)
at ij.ImageJ.runUserPlugIn(ImageJ.java:308)
at ij.IJ.runPlugIn(IJ.java:56)
at ij.Executer.runPlugIn(Executer.java:152)
at ij.Executer.runCommand(Executer.java:103)
at ij.Executer.run(Executer.java:60)
at java.lang.Thread.run(Thread.java:536)
In the past I have installed Java 1.1.8, 1.3.1, 1.4.0beta3, 1.4.0-rc and
1.4.0 final on my system. Now all the version before 1.4.0 final are
uninstalled.
On an other new installed Windows 2000 system both programs work fine
under 1.4.0 final.
Has anyone has an idea what could be wrong with my system?
Thanks
Thomas