Problems with Calendar addon - can't compile widgetset

Hi.
I’ve wanted to add Calendar (https://vaadin.com/directory/component/calendar-add-on) to my project.
So I’ve added dependency to my pom.xml.
When I run project with calendar component I’ve got error in place, where component was:
“Widgetset ‘com.vaadin.DefaultWidgetSet’ does not contain an implementation for org.vaadin.addon.calendar.Calendar site:vaadin.com”
I’ve read somwhere that I need to add “non-existing-module” to configuration and then compile widgetset.
So I did that and now when I compile widgetset it gives me a JS parser error.
Am I doing something wrong?

Here is widgetset compiling output:

[INFO]
 Scanning for projects...
[INFO]

[INFO]
 ------------------------------------------------------------------------
[INFO]
 Building portal 0.0.1-SNAPSHOT
[INFO]
 ------------------------------------------------------------------------
[INFO]

[INFO]
 --- vaadin-maven-plugin:8.2.0:update-widgetset (default-cli) @ portal ---
[INFO]
 Updating widgetset non-existing-module
[INFO]
 Adding resource directory to command classpath: C:\Users\Michu\SWZTZ\portal\src\main\resources
[INFO]
 Adding resource directory to command classpath: C:\Users\Michu\SWZTZ\portal\src\main\resources
[INFO]
 Widgetsets found from classpath:
[INFO]
 org.vaadin.addon.calendar.WidgetSet in jar:file:C:/Users/Michu/.m2/repository/org/vaadin/blackbluegl/calendar-component/2.0-BETA3/calendar-component-2.0-BETA3.jar!/
[INFO]
 com.vaadin.DefaultWidgetSet in jar:file:C:/Users/Michu/.m2/repository/com/vaadin/vaadin-client/8.2.0/vaadin-client-8.2.0.jar!/
[INFO]
 Addon styles found from classpath:
[INFO]
 VAADIN/addons/calendar/calendar-addon.scss in jar:file:C:/Users/Michu/.m2/repository/org/vaadin/blackbluegl/calendar-component/2.0-BETA3/calendar-component-2.0-BETA3.jar!/
[INFO]

[INFO]
 Search took 8ms
[INFO]

[INFO]
 --- vaadin-maven-plugin:8.2.0:compile (default-cli) @ portal ---
[INFO]
 Compiling module non-existing-module
[INFO]
 Computing all possible rebind results for 'com.vaadin.client.metadata.ConnectorBundleLoader'
[INFO]
 Rebinding com.vaadin.client.metadata.ConnectorBundleLoader
[INFO]
 Invoking generator com.vaadin.server.widgetsetutils.ConnectorBundleLoaderFactory
[INFO]
 Populating eager bundle
[INFO]
 Visiting DataCommunicatorConnector with ConnectorInitVisitor
[INFO]
 DataCommunicatorConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.extension.datacommunicator.DataCommunicatorState as a bean
[INFO]
 Will serialize class com.vaadin.shared.communication.URLReference using URLReference_Serializer
[INFO]
 Visiting HierarchicalDataCommunicatorConnector with ConnectorInitVisitor
[INFO]
 HierarchicalDataCommunicatorConnector will be in the eager bundle
[INFO]
 Visiting JavaScriptExtension with ConnectorInitVisitor
[INFO]
 JavaScriptExtension will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.JavaScriptExtensionState as a bean
[INFO]
 Visiting BrowserWindowOpenerConnector with ConnectorInitVisitor
[INFO]
 BrowserWindowOpenerConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.BrowserWindowOpenerState as a bean
[INFO]
 Visiting FileDownloaderConnector with ConnectorInitVisitor
[INFO]
 FileDownloaderConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.extension.filedownloader.FileDownloaderState as a bean
[INFO]
 Visiting ResponsiveConnector with ConnectorInitVisitor
[INFO]
 ResponsiveConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.extension.responsive.ResponsiveState as a bean
[INFO]
 Visiting AbsoluteLayoutConnector with ConnectorInitVisitor
[INFO]
 AbsoluteLayoutConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.absolutelayout.AbsoluteLayoutState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.ContentMode as an enum
[INFO]
 Will serialize class com.vaadin.shared.ui.ErrorLevel as an enum
[INFO]
 Visiting JavaScriptComponentConnector with ConnectorInitVisitor
[INFO]
 JavaScriptComponentConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.JavaScriptComponentState as a bean
[INFO]
 Visiting DateFieldConnector with ConnectorInitVisitor
[INFO]
 DateFieldConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.datefield.LocalDateFieldState as a bean
[INFO]
 Will serialize class java.util.Date using Date_Serializer
[INFO]
 Visiting DateTimeFieldConnector with ConnectorInitVisitor
[INFO]
 DateTimeFieldConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.datefield.LocalDateTimeFieldState as a bean
[INFO]
 Visiting AccordionConnector with ConnectorInitVisitor
[INFO]
 AccordionConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.accordion.AccordionState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.tabsheet.TabState as a bean
[INFO]
 Visiting AudioConnector with ConnectorInitVisitor
[INFO]
 AudioConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.audio.AudioState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.PreloadMode as an enum
[INFO]
 Visiting BrowserFrameConnector with ConnectorInitVisitor
[INFO]
 BrowserFrameConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.browserframe.BrowserFrameState as a bean
[INFO]
 Visiting ButtonConnector with ConnectorInitVisitor
[INFO]
 ButtonConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.button.ButtonState as a bean
[INFO]
 Visiting CheckBoxConnector with ConnectorInitVisitor
[INFO]
 CheckBoxConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.checkbox.CheckBoxState as a bean
[INFO]
 Visiting CheckBoxGroupConnector with ConnectorInitVisitor
[INFO]
 CheckBoxGroupConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.optiongroup.CheckBoxGroupState as a bean
[INFO]
 Visiting ComboBoxConnector with ConnectorInitVisitor
[INFO]
 ComboBoxConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.combobox.ComboBoxState as a bean
[INFO]
 Visiting CompositeConnector with ConnectorInitVisitor
[INFO]
 CompositeConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.AbstractComponentState as a bean
[INFO]
 Visiting CssLayoutConnector with ConnectorInitVisitor
[INFO]
 CssLayoutConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.csslayout.CssLayoutState as a bean
[INFO]
 Visiting CustomComponentConnector with ConnectorInitVisitor
[INFO]
 CustomComponentConnector will be in the eager bundle
[INFO]
 Visiting CustomFieldConnector with ConnectorInitVisitor
[INFO]
 CustomFieldConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.customfield.CustomFieldState as a bean
[INFO]
 Visiting CustomLayoutConnector with ConnectorInitVisitor
[INFO]
 CustomLayoutConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.customlayout.CustomLayoutState as a bean
[INFO]
 Visiting PopupDateFieldConnector with ConnectorInitVisitor
[INFO]
 PopupDateFieldConnector will be in the eager bundle
[INFO]
 Visiting PopupDateTimeFieldConnector with ConnectorInitVisitor
[INFO]
 PopupDateTimeFieldConnector will be in the eager bundle
[INFO]
 Visiting DragAndDropWrapperConnector with ConnectorInitVisitor
[INFO]
 DragAndDropWrapperConnector will be in the eager bundle
[INFO]
 Visiting EmbeddedConnector with ConnectorInitVisitor
[INFO]
 EmbeddedConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.embedded.EmbeddedState as a bean
[INFO]
 Visiting FlashConnector with ConnectorInitVisitor
[INFO]
 FlashConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.flash.FlashState as a bean
[INFO]
 Visiting FormLayoutConnector with ConnectorInitVisitor
[INFO]
 FormLayoutConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.orderedlayout.FormLayoutState as a bean
[INFO]
 Will serialize class java.util.HashMap<com.vaadin.shared.Connector, com.vaadin.shared.ui.orderedlayout.AbstractOrderedLayoutState.ChildComponentData> as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.orderedlayout.AbstractOrderedLayoutState.ChildComponentData as a bean
[INFO]
 Visiting GridConnector with ConnectorInitVisitor
[INFO]
 GridConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.GridState as a bean
[INFO]
 Will serialize com.vaadin.shared.data.sort.SortDirection as an array
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.SectionState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.SectionState.RowState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.HeightMode as an enum
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.ColumnResizeMode as an enum
[INFO]
 Will serialize java.lang.String as an array
[INFO]
 Will serialize class com.vaadin.shared.data.sort.SortDirection as an enum
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.SectionState.CellState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.GridStaticCellType as an enum
[INFO]
 Visiting ColumnConnector with ConnectorInitVisitor
[INFO]
 ColumnConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.ColumnState as a bean
[INFO]
 Visiting DetailsManagerConnector with ConnectorInitVisitor
[INFO]
 DetailsManagerConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.DetailsManagerState as a bean
[INFO]
 Visiting GridLayoutConnector with ConnectorInitVisitor
[INFO]
 GridLayoutConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.gridlayout.GridLayoutState as a bean
[INFO]
 Will serialize float as an array
[INFO]
 Will serialize class com.vaadin.shared.ui.gridlayout.GridLayoutState.ChildComponentData as a bean
[INFO]
 Visiting HorizontalLayoutConnector with ConnectorInitVisitor
[INFO]
 HorizontalLayoutConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.orderedlayout.HorizontalLayoutState as a bean
[INFO]
 Visiting HorizontalSplitPanelConnector with ConnectorInitVisitor
[INFO]
 HorizontalSplitPanelConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.splitpanel.HorizontalSplitPanelState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.splitpanel.AbstractSplitPanelState.SplitterState as a bean
[INFO]
 Visiting ImageConnector with ConnectorInitVisitor
[INFO]
 ImageConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.image.ImageState as a bean
[INFO]
 Visiting InlineDateFieldConnector with ConnectorInitVisitor
[INFO]
 InlineDateFieldConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.datefield.InlineDateFieldState as a bean
[INFO]
 Visiting InlineDateTimeFieldConnector with ConnectorInitVisitor
[INFO]
 InlineDateTimeFieldConnector will be in the eager bundle
[INFO]
 Visiting JavaScriptManagerConnector with ConnectorInitVisitor
[INFO]
 JavaScriptManagerConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.extension.javascriptmanager.JavaScriptManagerState as a bean
[INFO]
 Visiting LabelConnector with ConnectorInitVisitor
[INFO]
 LabelConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.label.LabelState as a bean
[INFO]
 Visiting LinkConnector with ConnectorInitVisitor
[INFO]
 LinkConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.link.LinkState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.BorderStyle as an enum
[INFO]
 Visiting ListSelectConnector with ConnectorInitVisitor
[INFO]
 ListSelectConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.listselect.ListSelectState as a bean
[INFO]
 Visiting LoginFormConnector with ConnectorInitVisitor
[INFO]
 LoginFormConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.loginform.LoginFormState as a bean
[INFO]
 Visiting MenuBarConnector with ConnectorInitVisitor
[INFO]
 MenuBarConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.menubar.MenuBarState as a bean
[INFO]
 Visiting NativeButtonConnector with ConnectorInitVisitor
[INFO]
 NativeButtonConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.button.NativeButtonState as a bean
[INFO]
 Visiting NativeSelectConnector with ConnectorInitVisitor
[INFO]
 NativeSelectConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.nativeselect.NativeSelectState as a bean
[INFO]
 Visiting NotificationConnector with ConnectorInitVisitor
[INFO]
 NotificationConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.notification.NotificationState as a bean
[INFO]
 Will serialize class com.vaadin.shared.Position as an enum
[INFO]
 Visiting PanelConnector with ConnectorInitVisitor
[INFO]
 PanelConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.panel.PanelState as a bean
[INFO]
 Visiting PasswordFieldConnector with ConnectorInitVisitor
[INFO]
 PasswordFieldConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.passwordfield.PasswordFieldState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.ValueChangeMode as an enum
[INFO]
 Visiting PopupViewConnector with ConnectorInitVisitor
[INFO]
 PopupViewConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.popupview.PopupViewState as a bean
[INFO]
 Visiting ProgressBarConnector with ConnectorInitVisitor
[INFO]
 ProgressBarConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.progressindicator.ProgressBarState as a bean
[INFO]
 Visiting RadioButtonGroupConnector with ConnectorInitVisitor
[INFO]
 RadioButtonGroupConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.optiongroup.RadioButtonGroupState as a bean
[INFO]
 Visiting SliderConnector with ConnectorInitVisitor
[INFO]
 SliderConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.slider.SliderState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.slider.SliderOrientation as an enum
[INFO]
 Visiting TabsheetConnector with ConnectorInitVisitor
[INFO]
 TabsheetConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.tabsheet.TabsheetState as a bean
[INFO]
 Visiting TextAreaConnector with ConnectorInitVisitor
[INFO]
 TextAreaConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.textarea.TextAreaState as a bean
[INFO]
 Visiting TextFieldConnector with ConnectorInitVisitor
[INFO]
 TextFieldConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.textfield.TextFieldState as a bean
[INFO]
 Visiting TreeMultiSelectionModelConnector with ConnectorInitVisitor
[INFO]
 TreeMultiSelectionModelConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.tree.TreeMultiSelectionModelState as a bean
[INFO]
 Visiting TreeRendererConnector with ConnectorInitVisitor
[INFO]
 TreeRendererConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.tree.TreeRendererState as a bean
[INFO]
 Visiting TreeGridConnector with ConnectorInitVisitor
[INFO]
 TreeGridConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.treegrid.TreeGridState as a bean
[INFO]
 Visiting TwinColSelectConnector with ConnectorInitVisitor
[INFO]
 TwinColSelectConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.twincolselect.TwinColSelectState as a bean
[INFO]
 Visiting UIConnector with ConnectorInitVisitor
[INFO]
 UIConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.ui.UIState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.ui.UIState.LocaleServiceState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.ui.UIState.TooltipConfigurationState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.ui.UIState.LoadingIndicatorConfigurationState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.ui.UIState.ReconnectDialogConfigurationState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.ui.UIState.LocaleData as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.ui.PageState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.ui.UIState.NotificationTypeConfiguration as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.ui.NotificationRole as an enum
[INFO]
 Will serialize class com.vaadin.shared.ui.ui.UIState.PushConfigurationState as a bean
[INFO]
 Will serialize class com.vaadin.shared.communication.PushMode as an enum
[INFO]
 Visiting UploadConnector with ConnectorInitVisitor
[INFO]
 UploadConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.upload.UploadState as a bean
[INFO]
 Visiting VerticalLayoutConnector with ConnectorInitVisitor
[INFO]
 VerticalLayoutConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.orderedlayout.VerticalLayoutState as a bean
[INFO]
 Visiting VerticalSplitPanelConnector with ConnectorInitVisitor
[INFO]
 VerticalSplitPanelConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.splitpanel.VerticalSplitPanelState as a bean
[INFO]
 Visiting VideoConnector with ConnectorInitVisitor
[INFO]
 VideoConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.video.VideoState as a bean
[INFO]
 Visiting WindowConnector with ConnectorInitVisitor
[INFO]
 WindowConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.window.WindowState as a bean
[INFO]
 Will serialize com.vaadin.shared.Connector as an array
[INFO]
 Will serialize class com.vaadin.shared.ui.window.WindowRole as an enum
[INFO]
 Will serialize class com.vaadin.shared.ui.window.WindowMode as an enum
[INFO]
 Visiting EditorConnector with ConnectorInitVisitor
[INFO]
 EditorConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.editor.EditorState as a bean
[INFO]
 Visiting GridDragSourceConnector with ConnectorInitVisitor
[INFO]
 GridDragSourceConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.GridDragSourceState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.dnd.EffectAllowed as an enum
[INFO]
 Will serialize class com.vaadin.shared.ui.dnd.criteria.Payload as a bean
[INFO]
 Visiting GridDropTargetConnector with ConnectorInitVisitor
[INFO]
 GridDropTargetConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.GridDropTargetState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.DropMode as an enum
[INFO]
 Will serialize class com.vaadin.shared.ui.dnd.criteria.Criterion as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.dnd.criteria.Criterion.Match as an enum
[INFO]
 Will serialize class com.vaadin.shared.ui.dnd.DropEffect as an enum
[INFO]
 Visiting MultiSelectionModelConnector with ConnectorInitVisitor
[INFO]
 MultiSelectionModelConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.MultiSelectionModelState as a bean
[INFO]
 Visiting NoSelectionModelConnector with ConnectorInitVisitor
[INFO]
 NoSelectionModelConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.communication.SharedState as a bean
[INFO]
 Visiting SingleSelectionModelConnector with ConnectorInitVisitor
[INFO]
 SingleSelectionModelConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.SingleSelectionModelState as a bean
[INFO]
 Visiting TreeGridDragSourceConnector with ConnectorInitVisitor
[INFO]
 TreeGridDragSourceConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.treegrid.TreeGridDragSourceState as a bean
[INFO]
 Visiting TreeGridDropTargetConnector with ConnectorInitVisitor
[INFO]
 TreeGridDropTargetConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.treegrid.TreeGridDropTargetState as a bean
[INFO]
 Visiting DragSourceExtensionConnector with ConnectorInitVisitor
[INFO]
 DragSourceExtensionConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.dnd.DragSourceState as a bean
[INFO]
 Visiting DropTargetExtensionConnector with ConnectorInitVisitor
[INFO]
 DropTargetExtensionConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.dnd.DropTargetState as a bean
[INFO]
 Visiting FileDropTargetConnector with ConnectorInitVisitor
[INFO]
 FileDropTargetConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.dnd.FileDropTargetState as a bean
[INFO]
 Visiting JavaScriptRendererConnector with ConnectorInitVisitor
[INFO]
 JavaScriptRendererConnector will be in the eager bundle
[INFO]
 Visiting ButtonRendererConnector with ConnectorInitVisitor
[INFO]
 ButtonRendererConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.renderers.ButtonRendererState as a bean
[INFO]
 Visiting ComponentRendererConnector with ConnectorInitVisitor
[INFO]
 ComponentRendererConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.renderers.ComponentRendererState as a bean
[INFO]
 Visiting DateRendererConnector with ConnectorInitVisitor
[INFO]
 DateRendererConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.renderers.DateRendererState as a bean
[INFO]
 Visiting UnsafeHtmlRendererConnector with ConnectorInitVisitor
[INFO]
 UnsafeHtmlRendererConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.renderers.HtmlRendererState as a bean
[INFO]
 Visiting ImageRendererConnector with ConnectorInitVisitor
[INFO]
 ImageRendererConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.renderers.ImageRendererState as a bean
[INFO]
 Visiting LocalDateRendererConnector with ConnectorInitVisitor
[INFO]
 LocalDateRendererConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.renderers.LocalDateRendererState as a bean
[INFO]
 Visiting LocalDateTimeRendererConnector with ConnectorInitVisitor
[INFO]
 LocalDateTimeRendererConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.renderers.LocalDateTimeRendererState as a bean
[INFO]
 Visiting NumberRendererConnector with ConnectorInitVisitor
[INFO]
 NumberRendererConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.renderers.NumberRendererState as a bean
[INFO]
 Visiting ProgressBarRendererConnector with ConnectorInitVisitor
[INFO]
 ProgressBarRendererConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.renderers.ProgressBarRendererState as a bean
[INFO]
 Visiting TextRendererConnector with ConnectorInitVisitor
[INFO]
 TextRendererConnector will be in the eager bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.renderers.TextRendererState as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.ScrollDestination as an enum
[INFO]
 Will serialize class com.vaadin.shared.MouseEventDetails as a bean
[INFO]
 Will serialize class com.vaadin.shared.MouseEventDetails.MouseButton as an enum
[INFO]
 Will serialize class org.vaadin.addon.calendar.client.ui.schedule.SelectionRange as a bean
[INFO]
 Will serialize class org.vaadin.addon.calendar.client.ui.schedule.CalDate as a bean
[INFO]
 Will serialize class org.vaadin.addon.calendar.client.ui.schedule.CalTime as a bean
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.GridConstants.Section as an enum
[INFO]
 Will serialize class com.vaadin.shared.ui.grid.DropLocation as an enum
[INFO]
 Will serialize class com.vaadin.shared.ui.dnd.FileParameters as a bean
[INFO]
 Populating ColorPickerConnector bundle
[INFO]
 Visiting ColorPickerConnector with ConnectorInitVisitor
[INFO]
 ColorPickerConnector will be in the com.vaadin.client.ui.colorpicker.ColorPickerConnector bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.colorpicker.ColorPickerState as a bean
[INFO]
 Populating ColorPickerAreaConnector bundle
[INFO]
 Visiting ColorPickerAreaConnector with ConnectorInitVisitor
[INFO]
 ColorPickerAreaConnector will be in the com.vaadin.client.ui.colorpicker.ColorPickerAreaConnector bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.colorpicker.ColorPickerAreaState as a bean
[INFO]
 Populating RichTextAreaConnector bundle
[INFO]
 Visiting RichTextAreaConnector with ConnectorInitVisitor
[INFO]
 RichTextAreaConnector will be in the com.vaadin.client.ui.richtextarea.RichTextAreaConnector bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.richtextarea.RichTextAreaState as a bean
[INFO]
 Populating ColorPickerGradientConnector bundle
[INFO]
 Visiting ColorPickerGradientConnector with ConnectorInitVisitor
[INFO]
 ColorPickerGradientConnector will be in the com.vaadin.client.ui.colorpicker.ColorPickerGradientConnector bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.colorpicker.ColorPickerGradientState as a bean
[INFO]
 Populating ColorPickerGridConnector bundle
[INFO]
 Visiting ColorPickerGridConnector with ConnectorInitVisitor
[INFO]
 ColorPickerGridConnector will be in the com.vaadin.client.ui.colorpicker.ColorPickerGridConnector bundle
[INFO]
 Will serialize class com.vaadin.shared.ui.colorpicker.ColorPickerGridState as a bean
[INFO]
 Populating CalendarConnector bundle
[INFO]
 Visiting CalendarConnector with ConnectorInitVisitor
[INFO]
 CalendarConnector will be in the org.vaadin.addon.calendar.client.CalendarConnector bundle
[INFO]
 Will serialize class org.vaadin.addon.calendar.client.CalendarState as a bean
[INFO]
 Will serialize class org.vaadin.addon.calendar.client.CalendarState.ItemSortOrder as an enum
[INFO]
 Will serialize class org.vaadin.addon.calendar.client.CalendarState.Item as a bean
[INFO]
 Will serialize class org.vaadin.addon.calendar.client.CalendarState.Day as a bean
[INFO]
 Will serialize class org.vaadin.addon.calendar.client.CalendarState.Action as a bean
[INFO]
 Computing all possible rebind results for 'com.vaadin.client.ui.dd.VAcceptCriterionFactory'
[INFO]
 Rebinding com.vaadin.client.ui.dd.VAcceptCriterionFactory
[INFO]
 Invoking generator com.vaadin.server.widgetsetutils.AcceptCriteriaFactoryGenerator
[INFO]
 Detecting available criteria ...
[INFO]
 creating mapping for com.vaadin.event.dd.acceptcriteria.AcceptAll
[INFO]
 creating mapping for com.vaadin.event.dd.acceptcriteria.And
[INFO]
 creating mapping for com.vaadin.event.dd.acceptcriteria.ContainsDataFlavor
[INFO]
 creating mapping for com.vaadin.event.dd.acceptcriteria.SourceIs
[INFO]
 creating mapping for com.vaadin.event.dd.acceptcriteria.Not
[INFO]
 creating mapping for com.vaadin.event.dd.acceptcriteria.Or
[INFO]
 creating mapping for com.vaadin.event.dd.acceptcriteria.ServerSideCriterion
[INFO]
 creating mapping for com.vaadin.event.dd.acceptcriteria.SourceIsTarget
[INFO]
 creating mapping for com.vaadin.event.dd.acceptcriteria.TargetDetailIs
[INFO]
 Done. (0seconds)
[INFO]
 Compiling 1 permutation
[INFO]
 Compiling permutation 0...
[INFO]
 Compile of permutations succeeded
[INFO]
 Compilation succeeded -- 64,335s
[INFO]
 Linking into C:\Users\Michu\SWZTZ\portal\src\main\webapp\VAADIN\widgetsets\non-existing-module; Writing extras to C:\Users\Michu\SWZTZ\portal\target\extra\non-existing-module
[INFO]
 Invoking Linker Cross-Site-Iframe
[INFO]
 Attempting to optimize JS
[INFO]
 [ERROR]
 Unable to parse JavaScript
[INFO]
 com.google.gwt.dev.js.JsParserException: StandardLinkerContext.optimizeJavaScript(17): missing ( before function parameters
[INFO]
 > function non-existing-module() {
[INFO]
 > -------------^
[INFO]
 at com.google.gwt.dev.js.JsParser$1.error(JsParser.java:111)
[INFO]
 at com.google.gwt.dev.js.rhino.Context.reportError(Context.java:459)
[INFO]
 at com.google.gwt.dev.js.rhino.TokenStream.reportSyntaxError(TokenStream.java:1594)
[INFO]
 at com.google.gwt.dev.js.rhino.Parser.reportError(Parser.java:72)
[INFO]
 at com.google.gwt.dev.js.rhino.Parser.mustMatchToken(Parser.java:64)
[INFO]
 at com.google.gwt.dev.js.rhino.Parser.function(Parser.java:189)
[INFO]
 at com.google.gwt.dev.js.rhino.Parser.parse(Parser.java:116)
[INFO]
 at com.google.gwt.dev.js.JsParser.parseImpl(JsParser.java:133)
[INFO]
 at com.google.gwt.dev.js.JsParser.parse(JsParser.java:88)
[INFO]
 at com.google.gwt.dev.js.JsParser.parseInto(JsParser.java:93)
[INFO]
 at com.google.gwt.core.ext.linker.impl.StandardLinkerContext.optimizeJavaScript(StandardLinkerContext.java:443)
[INFO]
 at com.google.gwt.core.ext.linker.impl.SelectionScriptLinker.generateSelectionScript(SelectionScriptLinker.java:428)
[INFO]
 at com.google.gwt.core.ext.linker.impl.SelectionScriptLinker.generateSelectionScript(SelectionScriptLinker.java:416)
[INFO]
 at com.google.gwt.core.ext.linker.impl.SelectionScriptLinker.emitSelectionScript(SelectionScriptLinker.java:310)
[INFO]
 at com.google.gwt.core.ext.linker.impl.SelectionScriptLinker.link(SelectionScriptLinker.java:212)
[INFO]
 at com.google.gwt.core.ext.linker.impl.StandardLinkerContext.invokeFinalLink(StandardLinkerContext.java:339)
[INFO]
 at com.google.gwt.dev.Link.doSimulatedShardingLink(Link.java:459)
[INFO]
 at com.google.gwt.dev.Link.link(Link.java:178)
[INFO]
 at com.google.gwt.dev.Compiler.compile(Compiler.java:244)
[INFO]
 at com.google.gwt.dev.Compiler.compile(Compiler.java:155)
[INFO]
 at com.google.gwt.dev.Compiler.compile(Compiler.java:144)
[INFO]
 at com.google.gwt.dev.Compiler$1.run(Compiler.java:118)
[INFO]
 at com.google.gwt.dev.CompileTaskRunner.doRun(CompileTaskRunner.java:55)
[INFO]
 at com.google.gwt.dev.CompileTaskRunner.runWithAppropriateLogger(CompileTaskRunner.java:50)
[INFO]
 at com.google.gwt.dev.Compiler.main(Compiler.java:125)
[INFO]
 ------------------------------------------------------------------------
[INFO]
 BUILD FAILURE
[INFO]
 ------------------------------------------------------------------------
[INFO]
 Total time: 01:15 min
[INFO]
 Finished at: 2018-01-02T16:35:07+01:00
[INFO]
 Final Memory: 34M/363M
[INFO]
 ------------------------------------------------------------------------
[ERROR]
 Failed to execute goal com.vaadin:vaadin-maven-plugin:8.2.0:compile (default-cli) on project portal: Command [[
[ERROR]
 C:\Program Files\Java\jdk1.8.0_112\jre\bin\java -Xmx1G -Dgwt.persistentunitcache=false com.google.gwt.dev.Compiler -logLevel INFO -style OBF -war C:\Users\Michu\SWZTZ\portal\src\main\webapp\VAADIN\widgetsets -localWorkers 8 -failOnError -compileReport -XfragmentCount -1 -sourceLevel auto -extra C:\Users\Michu\SWZTZ\portal\target\extra -gen C:\Users\Michu\SWZTZ\portal\target\.generated non-existing-module
[ERROR]
 ]] failed with status 1
[ERROR]
 -> [Help 1]

[ERROR]

[ERROR]
 To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR]
 Re-run Maven using the -X switch to enable full debug logging.
[ERROR]

[ERROR]
 For more information about the errors and possible solutions, please read the following articles:
[ERROR]
 [Help 1]
 http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

And here is my pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>pl.swztz</groupId>
    <artifactId>portal</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>portal</name>
    <description>Portal SWZTZ</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <vaadin.version>8.2.0</vaadin.version>
    </properties>

    <repositories>
          <repository>
               <id>vaadin-addons</id>
               <url>http://maven.vaadin.com/vaadin-addons</url>
        </repository>
    </repositories>
    
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>com.microsoft.sqlserver</groupId>
            <artifactId>mssql-jdbc</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
               <groupId>org.vaadin.addon</groupId>
               <artifactId>confirmdialog</artifactId>
               <version>3.2.0</version>
        </dependency>
        <dependency>
               <groupId>org.vaadin.blackbluegl</groupId>
               <artifactId>calendar-component</artifactId>
               <version>2.0-BETA3</version>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-client-compiler</artifactId>
            <version>${vaadin.version}</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-themes</artifactId>
            <version>${vaadin.version}</version>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>com.vaadin</groupId>
                <artifactId>vaadin-bom</artifactId>
                <version>${vaadin.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <finalName>PortalSWZTZ</finalName>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-war-plugin</artifactId>
                    <configuration>
                        <failOnMissingWebXml>false</failOnMissingWebXml>
                    </configuration>
                </plugin>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.0.0</version>
                    <configuration>
                        <filesets>
                            <fileset>
                                <directory>src/main/webapp/VAADIN/widgetsets</directory>
                            </fileset>
                            <fileset>
                                <directory>src/main/webapp/VAADIN/gwt-unitCache</directory>
                            </fileset>
                        </filesets>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
                <plugin>
                    <groupId>com.vaadin</groupId>
                    <artifactId>vaadin-maven-plugin</artifactId>
                    <version>${vaadin.version}</version>
                    <configuration>
                        <webappDirectory>${basedir}/src/main/webapp/VAADIN/widgetsets</webappDirectory>
                        <hostedWebapp>${basedir}/src/main/webapp/VAADIN/widgetsets</hostedWebapp>
                        <noServer>true</noServer>
                        <draftCompile>false</draftCompile>
                        <style>OBF</style>
                        <strict>true</strict>
                        <compileReport>true</compileReport>
                        <runTarget>http://localhost:8080/</runTarget>
                        <modules>
                            <module>non-existing-module</module>
                        </modules>
                    </configuration>
                    <executions>
                        <execution>
                            <configuration>
                                <skipTests>${skipTests}</skipTests>
                            </configuration>
                            <goals>
                                <goal>resources</goal>
                                <goal>update-widgetset</goal>
                                <goal>compile</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>

</project>

OK. It’s working!
I changed “non-existing-module” in pom to “MyWidgetset.Widgetset.gwt.xml” and then added annotation @Widgetset(“MyWidgetset.Widgetset.gwt.xml”) to UI class.

Hello.
I have the same problem.
where are you add @Widgetset(“MyWidgetset.Widgetset.gwt.xml”) to UI class???
Do you show me with a photo?