CH.9 QUIZ QUESTIONS

A constructor can access __________. - a local variable defined in any method - a private instance variable - a public instance variable - a static variable

A method that is associated with an individual object is called ____________. - a static method - a class method - an instance method - an object method

A static data field can be accessed from any method in the same class. True or false?

A static method in a class can access the class variables in the same class? True or false?

A static method in a class can access the instance variables in the same class? True or false?

All data fields in an object have default values True or false?

An immutable class cannot have ____________ - public data fields - private data fields - public constructors - no-arg constructors - static data fields

An object is an instance of a _________. -program -class -method -data

Analyze the following code and choose the best answer: public class Foo { private int x; public static void main(String[] args) { Foo foo = new Foo(); System.out.println(foo.x); } } A-Since x is private, it cannot be accessed from an object foo. B-Since x is defined in the class Foo, it can be accessed by any method inside the class without using an object. You can write the code to access x without creating an object such as foo in this code. C-Since x is an instance variable, it cannot be directly used inside a main method. However, it can be accessed through an object such as foo in this code. D-You cannot create a self-referenced object; that is, foo is created inside the class Foo.

Analyze the following code: class Test { private double i; public Test(double i) { this.t( ); this.i = i; } public Test( ) { System.out.println("Default constructor"); this(1); } public void t( ) { System.out.println("Invoking t"); } } A- this.t( ) may be replaced by t( ). B- this.i may be replaced by i. C- this(1) must be called before System.out.println("Default constructor"). D- this(1) must be replaced by this(1.0).

____________ is invoked to create an object. A constructor The main method A method with a return type A method with the void return type

________ can be accessed from any instance method in the class. - A local variable - An instance variable - A static variable

________ can be accessed from any static method in the class. - A local variable - An instane variable - A static variable

You can use the ______ operator to access members of an object - . - ( ) - * - %

You should add the static keyword in the place of ? in Line ________ in the following code: public class Test { private int age; public ? int square (int n) { return n * n; } public ? int getAge( ) { return age; } }

You cannot use the private modifier on classes True or false?

You can declare two variables with the same name in ________. -a method one as a formal parameter and the other as a local variable -a block -two nested blocks in a method (two nested blocks means one being inside the other) -different methods in a class

Which of the following statements are true? -A default constructor is provided automatically if no constructors are explicitly declared in the class. -At least one constructor must always be defined explicitly. -Every class has a default constructor. -The default constructor is a no-arg constructor.

Advantage of encapsulation? A -Only public methods are needed B -Making the class final causes no consequential changes to other code. C -It changes the implementation without changing a class's contract and causes no consequential changes to other code. D -It changes a class's contract without changing the implementation and causes no consequential changes to other code.

* * * What is the value of times displayed? public class Test { public static void main (String[] args) { Count myCount = new Count( ); int times = 0; for (int i=0; i < 100; i++) increment(myCount, times); System.out.println( "myCount.count = " + myCount.count); System.out.println("times = " + times); } public static void increment(Count c, int times) { c.count++; times++; } } class Count { int count; Count(int c) { count = c; } Count( ) { count = 1; } } 101 100 99 98 0

* * * What is the printout of the second println statement in the main method? public class Foo { int i; static int s; public static void main(String[] args) { Foo f1 = new Foo( ); System.out.println("f1.i is" + f1.i + "f1.s is" + f1.s); Foo f2 = new Foo( ); System.out.println("f2.i is" + f2.i + "f2.s is" + f2.s); Foo f3 = new Foo( ); System.out.println("f3.i is" + f3.i + "f3.s is" + f3.s); } public Foo( ) { i++; s++; } } A- f2.i is 1 f2.s is 1 B- f2.i is 1 f2.s is 2 C- f2.i is 2 f2.s is 2 D- f2.i is 2 f2.s is 1

* * * Printout for the first statement in the main method? public class Test { private int i = 0; static int j = 0; public static void main(String[] args) { new Test( ); } public Test( ) { i++; j++; int i = 1; int j = 1; System.out.println("i is " + j + " j is " + j); } }

Suppose you declare Date d. d is now called __________. -an object -a reference variable for an object - an object value - a variable that holds an integer val

Each class in the file is compiled into a separate bytecode file True or false?

The pillars of object oriented programming are?

A super class is referred to as a _________ class and sub class is referred to as a __________.

What does polymorphism mean?

What is object oriented programming? Or inheritance?

Who is Ada Lovelace?