If you're seeing errors like this in Eclipse/Helios when you're editing an Android resource file, you're hitting
this Eclipse bug. The workaround is to go to Preferences > XML > XML Files > Editor and turn off Use inferred grammar in absense of DTD/Schema.
Problems occurred when invoking code from plug-in: "org.eclipse.jface".
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.EditorReference.getEditor(EditorReference.java:289)
at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditorBatched(WorkbenchPage.java:2863)
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.Display.sendEvent(Display.java:3776)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1367)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1390)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1375)
at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:1187)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3622)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3277)
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(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
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)
