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I need the answers to this quiz about java programming-(Answered)

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I need the answers to this quiz about java programming


Question 1 (5 points)

 

How many parameters does a default constructor have?

 

Question 1 options:

 


 

It depends on the constructor

 


 

It can have 0 or 1

 


 

Always has 1

 


 

It never has any

 

Save

 


 

Question 2 (5 points)

 

Which of the following statements is true about the class shown below?

 

class Quiz1A

 

{

 

private int array = new int[10];

 

public int getArray()

 

{

 

return array;

 

}

 

}

 

Question 2 options:

 


 

It is mutable because it has an accessor method that returns a reference to a mutable instance

 

variable

 


 

It is immutable

 


 

It is mutable because it contains a public method

 


 

It is mutable because it contains a mutator method

 

Save

 


 

Question 3 (5 points)

 

A method that is associated with an individual object is called __________.

 

Question 3 options:

 


 

a class method

 


 

an instance method

 


 

a static method

 


 

an object method

 

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Question 4 (5 points)

 

Given the declaration Circle x = new Circle[10], which of the following statement is most accurate?

 

Question 4 options:

 


 

x contains an array of ten int values.

 


 

x contains a reference to an array and each element in the array can hold a reference to a Circle

 

object.

 


 

x contains an array of ten objects of the Circle type.

 


 

x contains a reference to an array and each element in the array can hold a Circle object.

 


 

Save

 


 

Question 5 (5 points)

 

What is the output of the program shown below?

 

public class Quiz1B

 

{

 

public static void main(String args)

 

{

 

Count count = new Count();

 

int times = 0;

 

for (int i = 0; i < 100; i++)

 

increment(count, times);

 

System.out.println("times = " + times + " count = " + count.times);

 

}

 

public static void increment(Count count, int times)

 

{

 

count.times++;

 

times++;

 

}

 

}

 

class Count

 

{

 

int times;

 

public Count()

 

{

 

times = 1;

 

}

 

Question 5 options:

 


 

times = 0 count = 101

 


 

times = 100 count = 1

 


 

times = 0 count = 1

 


 

times = 100 count = 101

 


 

Question 6 (5 points)

 


 

When calling a method with an object argument, ___________ is passed.

 

Question 6 options:

 


 

the object is copied, then the reference of the copied object

 


 

the contents of the object

 


 

a copy of the object

 


 

the reference of the object

 

Save

 


 

Question 7 (5 points)

 

Which of the following is not a property of a constructor?

 

Question 7 options:

 


 

The name of a constructor can be chosen by the programmer

 


 

A constructor must have the same name as the class

 


 

Constructors may be overloaded

 


 

A constructor is called using the new operator

 

Save

 


 

Question 8 (5 points)

 

What is the output of the program shown below?

 

public class Quiz1C

 

{

 

public static void main(String args)

 


 

{

 

int i = 1;

 

StringBuilder s = new StringBuilder("s");

 

String t = "t";

 

someMethod(i, s, t);

 

System.out.print("i = " + i + ", ");

 

System.out.print("s = " + s + ", ");

 

System.out.println("t = " + t);

 

}

 

private static void someMethod(int i, StringBuilder s, String t)

 

{

 

i++;

 

s.append("s");

 

t += "t";

 

}

 

}

 

Question 8 options:

 


 

i = 1, s = s, t = t

 


 

i = 2, s = ss, t = tt

 


 

i = 1, s = ss, t = t

 


 

i = 2, s = ss, t = t

 

Save

 


 

Question 9 (5 points)

 

Which of the following statements is true about the order of methods in a class.

 

Question 9 options:

 


 

They must be in alphabetical order by name

 


 

The order depends upon which compiler is used

 


 

They can be listed in any order

 


 

Each method must be listed before any method it calls

 

Save

 


 

Question 10 (5 points)

 

Which of the following statements about constructors is true?

 

Question 10 options:

 


 

There must be at least one constructor with no parameters

 


 

At least one constructor must always be defined explicitly

 


 

A default constructor is provided automatically if no constructors are explicitly declared in the

 

class

 


 

Every class has a default constructor

 

Save

 


 

Question 11 (5 points)

 

Which of the following is true about the program shown below?

 

class Quiz1D

 

{

 

private int x;

 

public Quiz1D(int x)

 

{

 

this.x = x;

 

}

 

}

 

Question 11 options:

 


 

If the this qualifier is removed, it will compile but won't initialize the instance variable

 


 

If the this qualifier is removed, it will still compile and properly initialize the instance variable

 


 

It will not compile if the this qualifier is removed

 


 

It will not compile because there it contains a duplicate variable

 

Save

 


 

Question 12 (5 points)

 

Which of the following statements about local variables is true?

 

Question 12 options:

 


 

Every method must have at least one local variable

 


 

Java assigns a default value to a local variable in a method if the variable is not initialized

 


 

A compilation error results when a local variable is accessed before it is initialized

 


 

Local variables retain their values from one method to the next

 

Save

 


 

Question 13 (5 points)

 

Analyze the code shown below and indicate which of the following is true:

 

class Quiz1E

 

{

 

private double variable;

 

public Quiz1E(double variable)

 

{

 

variable = variable;

 


 

}

 

}

 

Question 13 options:

 


 

The program does not compile because Quiz1E does not have a default constructor

 


 

The program has a compilation error because it does not have a main method

 


 

The program has a compilation error because you cannot assign variable to variable

 


 

The program will compile, but you cannot create an object of Quiz1E with a specified value for

 

variable

 

Save

 


 

Question 14 (5 points)

 

Which of the following is true of public methods?

 

Question 14 options:

 


 

They can only be accessed by methods in the same package

 


 

They can only be accessed by methods in the same class

 


 

They can only be accessed by methods in a different package

 


 

They can be accessed by any method in the same program

 

Save

 


 

Question 15 (5 points)

 

Which of the following statements is true about an immutable object?

 


 

Question 15 options:

 


 

An immutable object contains at least one mutator method

 


 

All instance variables of an immutable object must be public

 


 

The contents of an immutable object cannot be modified

 


 

All instance variables of an immutable object must be of primitive types.

 

Save

 


 

Question 16 (5 points)

 

What is the output of the program shown below?

 

public class Quiz1F

 

{

 

private static int i = 0;

 

public static void main(String args)

 

{

 

{

 

int i = 3;

 

}

 

System.out.println("i is " + i);

 

}

 

}

 

Question 16 options:

 


 

i is 0

 


 

i is 3

 


 

i is 2

 


 

i is 1

 


 

Save

 


 

Question 17 (5 points)

 

Which of the following statements is true of the reserved word this?

 

Question 17 options:

 


 

It can only be used in constructors

 


 

It can be only used in static methods

 


 

It can be only used in instance methods and constructors

 


 

It can be used in any method

 

Save

 


 

Question 18 (5 points)

 

Which of the following statements is true about the class shown below?

 

public class Quiz1G

 

{

 

private void method()

 

{

 

}

 

public static void main(String args)

 

{

 

method();

 

}

 

}

 

Question 18 options:

 


 

It won't compile because method must be declared after main

 


 

It won't compile because method must be public

 


 

It won't compile because method needs to be static

 


 

It will compile without any problem

 

Save

 


 

Question 19 (5 points)

 

Which of the following statements is true of private instance variables?

 

Question 19 options:

 


 

They can accessed in any instance method in the same class

 


 

They can be accessed by any class in the same program

 


 

They can be accessed by any class in the same package

 


 

They can only be accessed by static methods in the same class

 

Save

 


 

Question 20 (5 points)

 

Which of the following statements about class (static) variables is correct?

 

Question 20 options:

 


 

The number of copies of each class variable depends upon the code provided in the constructor

 


 

There is no way to predict how mant copies of a class variable will exits in any given program

 


 

Each instance of the class has a separate copy of very class variable

 


 

There is only one copy of each class variable that is shared by all instances of the class

 


 

 

Paper#9257586 | Written in 27-Jul-2016

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