Exam 10: Polymorphism

A JSlider provides a list of String choices that the user can select between.

What is printed? public class Inherit { abstract class Figure { void display( ) { System.out.println("Figure"); } } class Line extends Figure { void display( ) { System.out.println("Line"); } } void tryme(Figure f) { f.display( ); } Inherit( ) { Figure f = new Line( ); tryme(f); } public static void main(String[ ] args) { new Inherit( ); } }

Which of the following classes would you use to open a GUI dialog box, which is then used to select a file to open?

Write a set of code to define a vertical JSlider that goes from 1 to 1000 with tick marks every 100 and default to be set in the middle (at 500), with a background color of 0, 0, 255.

Assume that x is a GUI component from the javax.swing library. The instruction x.getValue( ) returns the value selected by the user from component x where x would be of which specific swing class?

What is printed? public class Inherit { class Figure { void display( ) { System.out.println("Figure"); } } class Rectangle extends Figure { void display( ) { System.out.println("Rectangle"); } } class Box extends Rectangle { void display( ) { System.out.println("Box"); } } Inherit( ) { Figure f = new Figure( ); Rectangle r = new Rectangle( ); Box b = new Box( ); f.display( ); f = r; ((Figure) f).display( ); f = (Figure) b; f.display( ); } public static void main(String[ ] args) { new Inherit( ); } }

A class reference can refer to any object of any class that descends from the class.

What is printed by the following code? Consider the polymorphic invocation. public class Inherit { class Figure { void display( ) { System.out.println("Figure"); } } class Rectangle extends Figure { void display( ) { System.out.println("Rectangle"); } } class Box extends Figure { void display( ) { System.out.println("Box"); } } Inherit( ) { Figure f = new Figure( ); Rectangle r = new Rectangle( ); Box b = new Box( ); f.display( ); f = r; f.display( ); f = b; f.display( ); } public static void main(String[ ] args) { new Inherit( ); } }

Binary search can be used on unsorted datait will just perform more slowly.

It is possible to sort an array of int, float, double or String, but not an array of an Object class such as a CD class.

Considering the event processing classes, what is the advantage of extending an adaptor class compared to implementing an interface?

One of the advantages of linear search is that it does not require its data to be sorted.

Write a set of code that will create 4 JButtons and add each of these to a JPanel so that they appear in a 2x2 grid. The JButtons will not have any text appear in them (i.e. no commands or names) but instead, will each appear as a color set by the user by using JColorChooser.

Write a set of code that will allow a user to select a file through a JFileChooser, read each item of the file, outputting each item to the screen, and close the file at the end.

Explain how to alter the Selection Sort algorithm so that it sorts in descending order instead of ascending order.

Explain why an abstract method cannot be declared private.

Write a set of code that will allow a user to select a file through a JFileChooser and store all items in the String array list to the selected file, closing the file when done.

The showDialog method is part of which class?

Which of the following GUI components would you use to allow the user to move the view of the components within the container?

Regarding the Software Failure: There was a segment in the Ariana 5 software to convert a floating-point number to a signed 16-bit integer, but once the number was converted, it was out of range for 16 bits.