Abstract Window Toolkit (AWT) Interview Questions And Answers

Swing is a GUI toolkit for Java. It is one part of the Java Foundation Classes (JFC). Swing includes graphical user interface (GUI) widgets such as text boxes, buttons, split-panes, and tables.

Swing widgets provide more sophisticated GUI components than the earlier Abstract Window Toolkit. Since they are written in pure Java, they run the same on all platforms, unlike the AWT which is tied to the underlying platform's windowing system. Swing supports pluggable look and feel – not by using the native platform's facilities, but by roughly emulating them. This means you can get any supported look and feel on any platform. The disadvantage of lightweight components is slower execution. The advantage is uniform behavior on all platforms.

A AWT stands for Abstract Window Toolkit. AWT enables programmers to develop Java applications with GUI components, such as windows, and buttons. The Java Virtual Machine (JVM) is responsible for translating the AWT calls into the appropriate calls to the host operating system.

A An event handler is a part of a computer program created to tell the program how to act in response to a specific event.

A Applet is a java program that runs inside a web browser.

A source is an object that generates an event. This occurs when the internal state of that object changes in some way. A listener is an object that is notified when an event occurs. It has two major requirements. First, it must have been registered with a source to receive notifications about specific event. Second, it must implement necessary methods to receive and process these notifications.

A Choice is displayed in a compact form that requires you to pull it down to see the list of available choices and only one item may be selected from a choice. A List may be displayed in such a way that several list items are visible and it supports the selection of one or more list items.

A layout manager is an object that is used to organize components in a container. The different layouts are available are FlowLayout, BorderLayout, CardLayout, GridLayout , GridBagLayout, Boxlayout and SpringLayout

There are two different types of applets. Trusted Applets and Untrusted applets. Trusted Applets are applets with predefined security and Untrusted Applets are applets without any security.

The FontMetrics class is used to define implementation-specific properties, such as ascent and descent, of a Font object.

A component can handle its own events by implementing the required event-listener interface and adding itself as its own event listener.

All AWT event listeners extend the java.util.EventListener interface.

Java Look-and-Feel.

Extension of java.

BorderLayout.

JFC supports robust and portable user interfaces. The Swing classes are robust, compatible with AWT, and provide you with a great deal of control over a user interface. Since source code is available, it is relatively easy to extend the JFC to do exactly what you need it to do. But the number of third-party controls written for Swing is still relatively small. WFC runs only on the Windows (32-bit) user interface, and uses Microsoft extensions to Java for event handling and ActiveX integration. Because ActiveX components are available to WFC programs, there are theoretically more controls available for WFC than for JFC. In practice, however, most ActiveX vendors do not actively support WFC, so the number of controls available for WFC is probably smaller than for JFC. The WFC programming model is closely aligned with the Windows platform.

Canvas is a component. ScrollPane is a container. Canvas is a rectangular area where the application can draw or trap input events. ScrollPane implements horizontal and vertical scrolling.

The CheckboxMenuItem class extends the MenuItem class to support a menu item that may be checked or unchecked.

A Canvas object provides access to a Graphics object via its paint() method.

When a window is repainted by the AWT painting thread, it sets the clipping regions to the area of the window that requires repainting.

This method is used to ensure that Swing components are updated through the event-dispatching thread.

Java uses layout managers to lay out components in a consistent manner across all windowing platforms. Since Java's layout managers aren't tied to absolute sizing and positioning, they are able to accommodate platform-specific differences among windowing systems.

The Frame class extends Window to define a main application window that can have a menu bar. A window can be modal.

The java.awt.AWTEvent class is the highest-level class in the AWT event-class hierarchy.

The enableEvents() method is used to enable an event for a particular object. Normally, an event is enabled when a listener is added to an object for a particular event. The enableEvents() method is used by objects that handle events by overriding their event-dispatch methods.

Converter is an application that converts distance measurements between metric and U.S units.