ADVANCED JAVA PART2

ADVANCED JAVA PART2

21. Which method of the Component class is used to set the position and size of a

component?

setBounds() method is used to set the position and size of a component.

22. What is the difference between yielding and sleeping?

When a task invokes its yield() method, it returns to the ready state. When a task invokes

its sleep()method, it returns to the waiting state.

23. Which java.util classes and interfaces support event handling?

The EventObject class and the EventListener interface support event processing.

24. Is sizeof a keyword?

The sizeof operator is not a keyword.

25. What are wrapped classes?

Wrapped classes are classes that allow primitive types to be accessed as objects.

26. Does garbage collection guarantee that a program will not run out of memory?

Garbage collection does not guarantee that a program will not run out of memory. It is possible for

programs to use up memory resources faster than they are garbage collected. It is also possible for

programs to create objects that are not subject to garbage collection.

27. What restrictions are placed on the location of a package statement within a source

code file?

A package statement must appear as the first line in a source code file (excluding blank lines and

comments).

28. Can an object's finalize() method be invoked while it is reachable?

An object's finalize() method cannot be invoked by the garbage collector while the object is still

reachable. However, an object's finalize() method may be invoked by other objects.

29. What is the immediate superclass of the Applet class?

Panel.

30. What is the difference between preemptive scheduling and time slicing?

Under preemptive scheduling, the highest priority task executes until it enters the waiting or dead

states or a higher priority task comes into existence. Under time slicing, a task executes for a

predefined slice of time and then reenters the pool of ready tasks.

The scheduler then determines which task should execute next, based on priority and other factors.

31. Name three Component subclasses that support painting.

The Canvas, Frame, Panel, and Applet classes support painting.

32. What value does readLine() return when it has reached the end of a file?

The readLine() method returns null when it has reached the end of a file.

33. What is the immediate superclass of the Dialog class?

Window.

34. What is clipping?

Clipping is the process of confining paint operations to a limited area or shape.

35. What is a native method?

A native method is a method that is implemented in a language other than Java.

36. Can a for statement loop indefinitely?

Yes, a for statement can loop indefinitely. For example, consider the following:

for(;;) ;

37. What are order of precedence and associativity, and how are they used?

Order of precedence determines the order in which operators are evaluated in expressions.

Associatity determines whether an expression is evaluated left-to-right or right-to-left.

38. When a thread blocks on I/O, what state does it enter?

A thread enters the waiting state when it blocks on I/O.

39. To what value is a variable of the String type automatically initialized?

The default value of an String type is null.

40. What is the catch or declare rule for method declarations?

If a checked exception may be thrown within the body of a method, the method must either catch the

exception or declare it in its throws clause.