Java Interview Questions - Page 10
Question: Which class should you use to obtain design information about an
object?
Answer: The Class class is used to obtain information about an object's
design.
Question: How can a GUI component handle its own events?
Answer: A component can handle
its own events by implementing the required event-listener interface and
adding itself as its own event listener.
Question: How are the elements of a GridBagLayout organized?
Answer: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.
Question: What advantage do Java's layout managers provide over traditional
windowing systems?
Answer: 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.
Question: What are the problems faced by Java programmers who don't use layout
managers?
Answer: 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.
Question: What is the difference between static and non-static variables?
Answer: 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.
Question: What is the difference between the paint() and repaint() methods?
Answer: 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.
Question: What is the purpose of the File class?
Answer: The File class is used to
create objects that provide access to the files and directories of a local
file system.
Question: What restrictions are placed on method overloading?
Answer: Two methods may
not have the same name and argument list but different return types.
Question: What restrictions are placed on method overriding?
Answer: Overridden methods
must have the same name, argument list, and return type. The overriding
method may not limit the access of the method it overrides. The overriding
method may not throw any exceptions that may not be thrown by the overridden
method.
Question: What is casting?
Answer: There are two types of casting, casting between
primitive numeric types and casting between object references. Casting
between numeric types is used to convert larger values, such as double
values, to smaller values, such as byte values. Casting between object
references is used to refer to an object by a compatible class, interface,
or array type reference.
Question: Name Container classes.
Answer: Window, Frame, Dialog, FileDialog, Panel,
Applet, or ScrollPane