Hello world problem
<p>I've got a problem with the basic HelloWorld program. I didn't change the basic program. But, when I want to open any *.xml in the folder "values" (in "res") an exception appears :</p>

<p><em>An error has occurred. See error log for more details.
java.lang.NullPointerException</em></p>

<p>and here is the exception stack trace:</p>

<pre><code>java.lang.NullPointerException
 at org.eclipse.wst.xml.core.internal.document.ElementImpl.getDefaultValue(ElementImpl.java:259)
 at org.eclipse.wst.xml.core.internal.document.ElementImpl.getAttributeNS(ElementImpl.java:329)
 at com.android.ide.eclipse.adt.internal.editors.uimodel.UiElementNode.getShortDescription(Unknown Source)
 at com.android.ide.eclipse.adt.internal.editors.ui.tree.UiModelTreeLabelProvider.getText(Unknown Source)
 at org.eclipse.jface.viewers.WrappedViewerLabelProvider.getText(WrappedViewerLabelProvider.java:108)
 at org.eclipse.jface.viewers.WrappedViewerLabelProvider.update(WrappedViewerLabelProvider.java:164)
 at org.eclipse.jface.viewers.ViewerColumn.refresh(ViewerColumn.java:152)
 at org.eclipse.jface.viewers.AbstractTreeViewer.doUpdateItem(AbstractTreeViewer.java:934)
 at org.eclipse.jface.viewers.AbstractTreeViewer$UpdateItemSafeRunnable.run(AbstractTreeViewer.java:102)
 at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
 at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:49)
 at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:175)
 at org.eclipse.jface.viewers.AbstractTreeViewer.doUpdateItem(AbstractTreeViewer.java:1014)
 at org.eclipse.jface.viewers.StructuredViewer$UpdateItemSafeRunnable.run(StructuredViewer.java:481)
 at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
 at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:49)
 at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:175)
 at org.eclipse.jface.viewers.StructuredViewer.updateItem(StructuredViewer.java:2141)
 at org.eclipse.jface.viewers.AbstractTreeViewer.updateChildren(AbstractTreeViewer.java:2689)
 at org.eclipse.jface.viewers.AbstractTreeViewer.internalRefreshStruct(AbstractTreeViewer.java:1867)
 at org.eclipse.jface.viewers.TreeViewer.internalRefreshStruct(TreeViewer.java:721)
 at org.eclipse.jface.viewers.AbstractTreeViewer.internalRefresh(AbstractTreeViewer.java:1842)
 at org.eclipse.jface.viewers.AbstractTreeViewer.internalRefresh(AbstractTreeViewer.java:1799)
 at org.eclipse.jface.viewers.AbstractTreeViewer.internalRefresh(AbstractTreeViewer.java:1785)
 at org.eclipse.jface.viewers.StructuredViewer$7.run(StructuredViewer.java:1487)
 at org.eclipse.jface.viewers.StructuredViewer.preservingSelection(StructuredViewer.java:1422)
 at org.eclipse.jface.viewers.TreeViewer.preservingSelection(TreeViewer.java:403)
 at org.eclipse.jface.viewers.StructuredViewer.preservingSelection(StructuredViewer.java:1383)
 at org.eclipse.jface.viewers.StructuredViewer.refresh(StructuredViewer.java:1485)
 at org.eclipse.jface.viewers.ColumnViewer.refresh(ColumnViewer.java:537)
 at org.eclipse.jface.viewers.StructuredViewer.refresh(StructuredViewer.java:1444)
 at org.eclipse.jface.viewers.ContentViewer.setContentProvider(ContentViewer.java:252)
 at org.eclipse.jface.viewers.StructuredViewer.setContentProvider(StructuredViewer.java:1641)
 at org.eclipse.jface.viewers.AbstractTreeViewer.setContentProvider(AbstractTreeViewer.java:2317)
 at org.eclipse.jface.viewers.TreeViewer.setContentProvider(TreeViewer.java:972)
 at com.android.ide.eclipse.adt.internal.editors.ui.tree.UiTreeBlock.changeRootAndDescriptors(Unknown Source)
 at com.android.ide.eclipse.adt.internal.editors.ui.tree.UiTreeBlock.createTreeViewer(Unknown Source)
 at com.android.ide.eclipse.adt.internal.editors.ui.tree.UiTreeBlock.createMasterPart(Unknown Source)
 at org.eclipse.ui.forms.MasterDetailsBlock.createContent(MasterDetailsBlock.java:161)
 at org.eclipse.ui.forms.MasterDetailsBlock.createContent(MasterDetailsBlock.java:142)
 at com.android.ide.eclipse.adt.internal.editors.resources.ResourcesTreePage.createFormContent(Unknown Source)
 at org.eclipse.ui.forms.editor.FormPage$1.run(FormPage.java:152)
 at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
 at org.eclipse.ui.forms.editor.FormPage.createPartControl(FormPage.java:150)
 at org.eclipse.ui.forms.editor.FormEditor.pageChange(FormEditor.java:471)
 at com.android.ide.eclipse.adt.internal.editors.AndroidEditor.pageChange(Unknown Source)
 at org.eclipse.ui.part.MultiPageEditorPart.setActivePage(MultiPageEditorPart.java:1067)
 at org.eclipse.ui.forms.editor.FormEditor.setActivePage(FormEditor.java:603)
 at com.android.ide.eclipse.adt.internal.editors.AndroidEditor.selectDefaultPage(Unknown Source)
 at com.android.ide.eclipse.adt.internal.editors.AndroidEditor.addPages(Unknown Source)
 at org.eclipse.ui.forms.editor.FormEditor.createPages(FormEditor.java:138)
 at org.eclipse.ui.part.MultiPageEditorPart.createPartControl(MultiPageEditorPart.java:348)
 at org.eclipse.ui.internal.EditorReference.createPartHelper(EditorReference.java:670)
 at org.eclipse.ui.internal.EditorReference.createPart(EditorReference.java:465)
 at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:595)
 at org.eclipse.ui.internal.PartPane.setVisible(PartPane.java:313)
 at org.eclipse.ui.internal.presentations.PresentablePart.setVisible(PresentablePart.java:180)
 at org.eclipse.ui.internal.presentations.util.PresentablePartFolder.select(PresentablePartFolder.java:270)
 at org.eclipse.ui.internal.presentations.util.LeftToRightTabOrder.select(LeftToRightTabOrder.java:65)
 at org.eclipse.ui.internal.presentations.util.TabbedStackPresentation.selectPart(TabbedStackPresentation.java:473)
 at org.eclipse.ui.internal.PartStack.refreshPresentationSelection(PartStack.java:1254)
 at org.eclipse.ui.internal.PartStack.setSelection(PartStack.java:1207)
 at org.eclipse.ui.internal.PartStack.showPart(PartStack.java:1606)
 at org.eclipse.ui.internal.PartStack.add(PartStack.java:497)
 at org.eclipse.ui.internal.EditorStack.add(EditorStack.java:103)
 at org.eclipse.ui.internal.PartStack.add(PartStack.java:483)
 at org.eclipse.ui.internal.EditorStack.add(EditorStack.java:112)
 at org.eclipse.ui.internal.EditorSashContainer.addEditor(EditorSashContainer.java:63)
 at org.eclipse.ui.internal.EditorAreaHelper.addToLayout(EditorAreaHelper.java:225)
 at org.eclipse.ui.internal.EditorAreaHelper.addEditor(EditorAreaHelper.java:213)
 at org.eclipse.ui.internal.EditorManager.createEditorTab(EditorManager.java:778)
 at org.eclipse.ui.internal.EditorManager.openEditorFromDescriptor(EditorManager.java:677)
 at org.eclipse.ui.internal.EditorManager.openEditor(EditorManager.java:638)
 at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditorBatched(WorkbenchPage.java:2860)
 at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditor(WorkbenchPage.java:2768)
 at org.eclipse.ui.internal.WorkbenchPage.access$11(WorkbenchPage.java:2760)
 at org.eclipse.ui.internal.WorkbenchPage$10.run(WorkbenchPage.java:2711)
 at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
 at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2707)
 at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2691)
 at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2682)
 at org.eclipse.ui.ide.IDE.openEditor(IDE.java:651)
 at org.eclipse.ui.ide.IDE.openEditor(IDE.java:610)
 at org.eclipse.jdt.internal.ui.javaeditor.EditorUtility.openInEditor(EditorUtility.java:365)
 at org.eclipse.jdt.internal.ui.javaeditor.EditorUtility.openInEditor(EditorUtility.java:168)
 at org.eclipse.jdt.ui.actions.OpenAction.run(OpenAction.java:229)
 at org.eclipse.jdt.ui.actions.OpenAction.run(OpenAction.java:208)
 at org.eclipse.jdt.ui.actions.SelectionDispatchAction.dispatchRun(SelectionDispatchAction.java:274)
 at org.eclipse.jdt.ui.actions.SelectionDispatchAction.run(SelectionDispatchAction.java:250)
 at org.eclipse.jdt.internal.ui.packageview.PackageExplorerActionGroup.handleOpen(PackageExplorerActionGroup.java:373)
 at org.eclipse.jdt.internal.ui.packageview.PackageExplorerPart$4.open(PackageExplorerPart.java:526)
 at org.eclipse.ui.OpenAndLinkWithEditorHelper$InternalListener.open(OpenAndLinkWithEditorHelper.java:48)
 at org.eclipse.jface.viewers.StructuredViewer$2.run(StructuredViewer.java:845)
 at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
 at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:49)
 at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:175)
 at org.eclipse.jface.viewers.StructuredViewer.fireOpen(StructuredViewer.java:843)
 at org.eclipse.jface.viewers.StructuredViewer.handleOpen(StructuredViewer.java:1131)
 at org.eclipse.jface.viewers.StructuredViewer$6.handleOpen(StructuredViewer.java:1235)
 at org.eclipse.jface.util.OpenStrategy.fireOpenEvent(OpenStrategy.java:264)
 at org.eclipse.jface.util.OpenStrategy.access$2(OpenStrategy.java:258)
 at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:298)
 at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
 at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
 at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4066)
 at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3657)
 at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2629)
 at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2593)
 at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2427)
 at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:670)
 at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
 at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:663)
 at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
 at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115)
 at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
 at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
 at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
 at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:369)
 at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
 at java.lang.reflect.Method.invoke(Unknown Source)
 at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:619)
 at org.eclipse.equinox.launcher.Main.basicRun(Main.java:574)
 at org.eclipse.equinox.launcher.Main.run(Main.java:1407)
 at org.eclipse.equinox.launcher.Main.main(Main.java:1383)
</code></pre>

<p>I don't know what I have to do.
Thanks
(Sorry for my bad english)</p>
