31.Which class is the superclass of all user-interface classes?
The class UIObject is the superclass for all user-interface objects.
32.Explain UIObject class.
The class UIObject is the superclass for all user-interface objects. It simply wraps a DOM element, and cannot receive events. It provides direct child classes like Widget, MenuItem, MenuItemSeparator, TreeItem.
All UIObject objects can be styled using CSS.
Every UIObject has a primary style name that identifies the key CSS style rule that should always be applied to it.
More complex styling behavior can be achieved by manipulating an object’s secondary style names.
33.Explain Widget class.
The class Widget is the base class for the majority of user-interface objects. Widget adds support for receiving events from the browser and being added directly to panels.
34.What is the purpose of Label widget of a GWT?
This widget contains text, not interpreted as HTML using a <div>element, causing it to be displayed with block layout.
35.What is the purpose of HTML widget of a GWT?
This widget can contain HTML text and displays the html content using a <div> element, causing it to be displayed with block layout.
36.What is the purpose of Image widget of a GWT?
This widget displays an image at a given URL.
37.What is the purpose of Anchor widget of GWT?
This widget represents a simple <a> element.
38..Which widget represents a standard push button in GWT?
Button widget represents a standard push button.
39Which widget represents a normal push button with custom styling in GWT?
PushButton represents a normal push button with custom styling.
40.Which widget represents a stylish stateful button which allows the user to toggle between up and down states in GWT?
ToggleButton widget represents a stylish stateful button which allows the user to toggle between up and down states.