java.lang.reflect.InvocationTargetException while refactoring

I'm trying to remove the spring roo nature out of my gvNix project. Following the steps here. When refactoring, as in the first step, an error is being raised. I tried to clean my project and reopen STS but still facing the same error. I only performed the web mvc setup after creating a simple entity and typicalsecurity setup commands.

My Stack trace

java.lang.reflect.InvocationTargetException
    at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:398)
    at org.eclipse.ltk.internal.ui.refactoring.RefactoringWizardDialog2.run(RefactoringWizardDialog2.java:319)
    at org.eclipse.ltk.ui.refactoring.RefactoringWizard.internalPerformFinish(RefactoringWizard.java:636)
    at org.eclipse.ltk.ui.refactoring.UserInputWizardPage.performFinish(UserInputWizardPage.java:145)
    at org.eclipse.ltk.ui.refactoring.RefactoringWizard.performFinish(RefactoringWizard.java:710)
    at org.eclipse.ltk.internal.ui.refactoring.RefactoringWizardDialog2.okPressed(RefactoringWizardDialog2.java:445)
    at org.eclipse.jface.dialogs.Dialog.buttonPressed(Dialog.java:466)
    at org.eclipse.jface.dialogs.Dialog$2.widgetSelected(Dialog.java:618)
    at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:249)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
    at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4415)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1079)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4233)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3821)
    at org.eclipse.jface.window.Window.runEventLoop(Window.java:818)
    at org.eclipse.jface.window.Window.open(Window.java:794)
    at org.eclipse.ltk.ui.refactoring.RefactoringWizardOpenOperation$1.run(RefactoringWizardOpenOperation.java:188)
    at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
    at org.eclipse.ltk.ui.refactoring.RefactoringWizardOpenOperation.run(RefactoringWizardOpenOperation.java:203)
    at org.eclipse.ltk.ui.refactoring.RefactoringWizardOpenOperation.run(RefactoringWizardOpenOperation.java:122)
    at org.eclipse.ajdt.internal.ui.refactoring.PushInRefactoringAction.run(PushInRefactoringAction.java:84)
    at org.eclipse.ajdt.internal.ui.refactoring.PushInRefactoringAction.run(PushInRefactoringAction.java:60)
    at org.eclipse.ui.internal.PluginAction.runWithEvent(PluginAction.java:247)
    at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:565)
    at org.eclipse.jface.action.ActionContributionItem.lambda$4(ActionContributionItem.java:397)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
    at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4415)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1079)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4233)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3821)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$4.run(PartRenderingEngine.java:1121)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1022)
    at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:150)
    at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:687)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
    at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:604)
    at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:148)
    at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:138)
    at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:388)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:243)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:673)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:610)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1519)
Caused by: java.lang.NullPointerException
    at org.eclipse.jdt.core.dom.rewrite.ImportRewrite.addImport(ImportRewrite.java:707)
    at org.eclipse.jdt.core.dom.rewrite.ImportRewrite.addImport(ImportRewrite.java:684)
    at org.eclipse.ajdt.internal.ui.refactoring.PushInRefactoring$PerUnitInformation.rewriteImports(PushInRefactoring.java:150)
    at org.eclipse.ajdt.internal.ui.refactoring.PushInRefactoring.checkFinalConditions(PushInRefactoring.java:336)
    at org.eclipse.ltk.core.refactoring.CheckConditionsOperation.run(CheckConditionsOperation.java:83)
    at org.eclipse.ltk.core.refactoring.CreateChangeOperation.run(CreateChangeOperation.java:119)
    at org.eclipse.ltk.core.refactoring.PerformChangeOperation.run(PerformChangeOperation.java:207)
    at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2240)
    at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2267)
    at org.eclipse.ltk.internal.ui.refactoring.WorkbenchRunnableAdapter.run(WorkbenchRunnableAdapter.java:86)
    at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:119)
Root exception:
java.lang.NullPointerException
    at org.eclipse.jdt.core.dom.rewrite.ImportRewrite.addImport(ImportRewrite.java:707)
    at org.eclipse.jdt.core.dom.rewrite.ImportRewrite.addImport(ImportRewrite.java:684)
    at org.eclipse.ajdt.internal.ui.refactoring.PushInRefactoring$PerUnitInformation.rewriteImports(PushInRefactoring.java:150)
    at org.eclipse.ajdt.internal.ui.refactoring.PushInRefactoring.checkFinalConditions(PushInRefactoring.java:336)
    at org.eclipse.ltk.core.refactoring.CheckConditionsOperation.run(CheckConditionsOperation.java:83)
    at org.eclipse.ltk.core.refactoring.CreateChangeOperation.run(CreateChangeOperation.java:119)
    at org.eclipse.ltk.core.refactoring.PerformChangeOperation.run(PerformChangeOperation.java:207)
    at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2240)
    at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2267)
    at org.eclipse.ltk.internal.ui.refactoring.WorkbenchRunnableAdapter.run(WorkbenchRunnableAdapter.java:86)
    at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:119)