What do heavy weight components mean in Java Programming?
Heavy weight components like Abstract Window Toolkit (AWT), depend on the local windowing toolkit. For example, java.awt.Button is a heavy weight component, when it is running on the Java platform for Unix platform, it maps to a real Motif button. In this relationship, the Motif button is called the peer to the java.awt.Button. If you create two Buttons, two peers and hence two Motif Buttons are also created. The Java platform communicates with the Motif Buttons using the Java Native Interface. For each and every component added to the application, there is an additional overhead tied to the local windowing system, which is why these components are called heavyweight.
Which package has light weight components in Java Programming?
javax.Swing package. All components in Swing, except JApplet, JDialog, JFrame and JWindow are lightweight components in Java Programming.
What are peerless components in Java Programming?
The peerless components are called light weight components.
What is the difference between the Font and FontMetrics classes in Java Programming?
The FontMetrics class is used to define implementation-specific properties, such as ascent and descent, of a Font object.
- What happens when a thread cannot acquire a lock on an object in Java Programming?
If a thread attempts to execute a synchronized method or synchronized statement and is unable to acquire an object’s lock, it enters the waiting state until the lock becomes available.
- What is the difference between the Reader/Writer class hierarchy and the InputStream/OutputStream class hierarchy in Java Programming?
The Reader/Writer class hierarchy is character-oriented, and the InputStream/OutputStream class hierarchy is byte-oriented.
- What classes of exceptions may be caught by a catch clause in Java Programming?
A catch clause can catch any exception that may be assigned to the Throwable type. This includes the Error and Exception types.
- If a class is declared without any access modifiers, where may the class be accessed in Java Programming?
A class that is declared without any access modifiers is said to have package or friendly access. This means that the class can only be accessed by other classes and interfaces that are defined within the same package.
What is the Map interface in Java Programming?
The Map interface replaces the JDK 1.1 Dictionary class and is used associate keys with values.
- Does a class inherit the constructors of its superclass in Java Programming?
A class does not inherit constructors from any of its superclasses.
Name primitive Java types?
The primitive types are byte, char, short, int, long, float, double, and boolean.
- Which class should you use to obtain design information about an object in Java Programming?
The Class class is used to obtain information about an object’s design.
- How can a GUI component handle its own events in Java Programming?
A component can handle its own events by implementing the required event-listener interface and adding itself as its own event listener.
- How are the elements of a GridBagLayout organized in Java Programming?
The elements of a GridBagLayout are organized according to a grid. However, the elements are of different sizes and may occupy more than one row or column of the grid. In addition, the rows and columns may have different sizes.
- What advantage do Java’s layout managers provide over traditional windowing systems?
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.
- What are the problems faced by Java programmers who don’t use layout managers?
Without layout managers, Java programmers are faced with determining how their GUI will be displayed across multiple windowing systems and finding a common sizing and positioning that will work within the constraints imposed by each windowing system.
- What is the difference between static and non-static variables in Java Programming?
A static variable is associated with the class as a whole rather than with specific instances of a class. Non-static variables take on unique values with each object instance.
- What is the difference between the paint() and repaint() methods in Java Programming?
The paint() method supports painting via a Graphics object. The repaint() method is used to cause paint() to be invoked by the AWT painting thread.
25 Aug 2013
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