ADVANCED JAVA PART 6

ADVANCED JAVA PART 6

101. Is "abc" a primitive value?

The String literal "abc" is not a primitive value. It is a String object.

102. What is the relationship between an event-listener interface and an event-adapter

class?

An event-listener interface defines the methods that must be implemented by an event handler for a

particular kind of event.

An event adapter provides a default implementation of an event-listener interface.

103. What restrictions are placed on the values of each case of a switch statement?

During compilation, the values of each case of a switch statement must evaluate to a value that can

be promoted to an int value.

104. What modifiers may be used with an interface declaration?

An interface may be declared as public or abstract.

105. Is a class a subclass of itself?

A class is a subclass of itself.

106. What is the highest-level event class of the event-delegation model?

The java.util.EventObject class is the highest-level class in the event-delegation class hierarchy.

107. What event results from the clicking of a button?

The ActionEvent event is generated as the result of the clicking of a button.

108. How can a GUI component handle its own events?

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

adding itself as its own event listener.

109. How are the elements of a GridBagLayout organized?

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.

110. 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

accomodate platform-specific differences among windowing systems.

111. What is the Collection interface?

The Collection interface provides support for the implementation of a mathematical bag - an

unordered collection of objects that may contain duplicates.

112. What modifiers can be used with a local inner class?

A local inner class may be final or abstract.

113. What is the difference between static and non-static variables?

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.

114. What is the difference between the paint() and repaint() methods?

The paint() method supports painting via a Graphics object. The repaint() method is used to

causepaint() to be invoked by the AWT painting thread.

115. What is the purpose of the File class?

The File class is used to create objects that provide access to the files and directories of a local file

system.

116. Can an exception be rethrown?

Yes, an exception can be rethrown.

117. Which Math method is used to calculate the absolute value of a number?

The abs() method is used to calculate absolute values.

118. How does multithreading take place on a computer with a single CPU?

The operating system's task scheduler allocates execution time to multiple tasks. By quickly switching

between executing tasks, it creates the impression that tasks execute sequentially.

119. When does the compiler supply a default constructor for a class?

The compiler supplies a default constructor for a class if no other constructors are provided.

120. When is the finally clause of a try-catch-finally statement executed?

The finally clause of the try-catch-finally statement is always executed unless the thread of execution

terminates or an exception occurs within the execution of the finally clause.