double[][] a=new double[4][5]; Mark for Review
(1) Points
True (*)
False
Incorrect Incorrect. Refer to Section 6 Lesson 1.
2. Which of the following declares and initializes a two dimensional array with 3 rows and 2 columns? Mark for Review
(1) Points
int a={{1,1,1},{1,1,1}};
int[][] a={{1,1,1},{1,1,1}};
int a={{1,1},{1,1},{1,1}};
int[][] a={{1,1},{1,1},{1,1}}; (*)
Incorrect Incorrect. Refer to Section 6 Lesson 1.
3. Which of the following declares and initializes a two dimensional array where each element is a reference type? Mark for Review
(1) Points
char[][] words=new char[10][4];
String words=new String[10];
char[][] words;
String[][] words=new String[10][3]; (*)
Incorrect Incorrect. Refer to Section 6 Lesson 1.
4. Which of the following statements add all of the elements of the one dimensional array prices, and then prints the sum to the screen? Mark for Review
(1) Points
int total = 0;
for(int i = 0; i total+=prices[i];
System.out.println(total); (*)
int total = 0;
for(int i = 0; i total+=prices[i];
int total = 0;
for(int i = 1; i total = total+prices[i];
System.out.println(prices);
int total = 0;
for(int i = 0; i total+=prices[i];
System.out.println(prices);
Incorrect Incorrect. Refer to Section 6 Lesson 1.
5. Which of the following declares and initializes a one dimensional array named words of size 10 so that all entries can be Strings? Mark for Review
(1) Points
char words=new char[10];
String[] words=new String[10]; (*)
String words=new String[10];
char[] words=new char[10];
6. What is the output of the following segment of code?
Mark for Review
(1) Points
321123
312213
This code doesn't compile.
642246 (*)
642
Incorrect Incorrect. Refer to Section 6 Lesson 1.
7. Which of the following declares and initializes a two dimensional array named values with 2 rows and 3 columns where each element is a reference to an Object? Mark for Review
(1) Points
String[][] values;
String[][] values={"apples","oranges","pears"};
String[][] values=new String[3][2];
String[][] values=new String[2][3]; (*)
Incorrect Incorrect. Refer to Section 6 Lesson 1.
8. What is the output of the following segment of code?
Mark for Review
(1) Points
111
1111
11 (*)
This code doesn't compile.
321111
Incorrect Incorrect. Refer to Section 6 Lesson 1.
9. What is the output of the following segment of code?
Mark for Review
(1) Points
262423242322
643432
This code does not compile.
1286864
666666 (*)
Incorrect Incorrect. Refer to Section 6 Lesson 1.
10. The following creates a reference in memory named z that can refer to seven different doubles via an index. True or false?
double z[] = new double[7]; Mark for Review
(1) Points
True (*)
False
Correct Correct
11. It is possible to throw and catch a second exception inside a catch block of code. True or false? Mark for Review
(1) Points
True (*)
False
Incorrect Incorrect. Refer to Section 6 Lesson 2.
12. Which of the following would give you an array index out of bounds exception? Mark for Review
(1) Points
Refering to an element of an array that is at an index less than the length of the array minus one.
Using a single equal symbol to compare the value of two integers.
Refering to an element of an array that is at an index greater than the length of that array minus one. (*)
Unintentionally placing a semicolon directly after initializing a for loop.
Misspelling a variable name somewhere in your code.
Incorrect Incorrect. Refer to Section 6 Lesson 2.
13. What do exceptions indicate in Java? Mark for Review
(1) Points
(Choose all correct answers)
Exceptions do not indicate anything, their only function is to be thrown.
The code was not written to handle all possible conditions. (*)
A mistake was made in your code. (*)
The code has considered and dealt with all possible cases.
There are no errors in your code.
Incorrect Incorrect. Refer to Section 6 Lesson 2.
14. If an exception is thrown by a method, where can the catch for the exception be? Mark for Review
(1) Points
The catch can be in the method that threw the exception or in any other method that called the method that threw the exception. (*)
The catch must be in the method that threw the exception.
There does not need to be a catch in this situation.
The catch must be immediately after the throw.
Incorrect Incorrect. Refer to Section 6 Lesson 2.
15. Suppose you misspell a method name when you call it in your program. Which of the following explains why this gives you an exception? Mark for Review
(1) Points
Because the interpreter does not recognize this method since it was never initialized, the correct spelling of the method was initialized.
Because the interpreter tries to read the method but when it finds the method you intended to use it crashes.
This will not give you an exception, it will give you an error when the program is compiled. (*)
Because the parameters of the method were not met.
Which of the following defines an Exception? Mark for Review
(1) Points
A very severe non-fixable problem with interpreting and running your code.
An interpreter reading your code.
A problem that can be corrected or handled by your code. (*)
Code that has no errors and therefore runs smothly.
Incorrect Incorrect. Refer to Section 6 Lesson 2.
2. What exception message indicates that a variable may have been mispelled somewhere in the program? Mark for Review
(1) Points
variableName cannot be resolved to a variable (*)
method methodName(int) is undefined for the type className
Syntax error, insert ";" to complete statement
All of the above
Incorrect Incorrect. Refer to Section 6 Lesson 2.
3. Which of the following correctly matches the symbol with its function? Mark for Review
(1) Points
(Choose all correct answers)
= (single equals sign) compares the value of primitive types such as int or char.
== (two equal signs) compares the values of non-primitive objects.
.equals() compares the value of non-primitive objects. (*)
== (two equal signs) compares the memory location of non-primitive objects. (*)
== (two equal signs) compares values of primitive types such as int or char. (*)
Incorrect Incorrect. Refer to Section 6 Lesson 2.
4. Suppose you misspell a method name when you call it in your program. Which of the following explains why this gives you an exception? Mark for Review
(1) Points
Because the parameters of the method were not met.
This will not give you an exception, it will give you an error when the program is compiled. (*)
Because the interpreter tries to read the method but when it finds the method you intended to use it crashes.
Because the interpreter does not recognize this method since it was never initialized, the correct spelling of the method was initialized.
Incorrect Incorrect. Refer to Section 6 Lesson 2.
5. A logic error occurs if an unintentional semicolon is placed at the end of a loop initiation because the interpreter reads this as the only line inside the loop, a line that does nothing. Everything that follows the semicolon is interpreted as code outside of the loop. True or false? Mark for Review
(1) Points
True
False (*)
6. The following array declaration is valid:
int[] y = new int[5]; Mark for Review
(1) Points
True (*)
False
Correct Correct
7. Which of the following declares and initializes a two dimensional array with 3 rows and 2 columns? Mark for Review
(1) Points
int[][] a={{1,1},{1,1},{1,1}}; (*)
int a={{1,1},{1,1},{1,1}};
int a={{1,1,1},{1,1,1}};
int[][] a={{1,1,1},{1,1,1}};
Correct Correct
8. Which of the following statements adds 5 to every element of the one dimensional array prices and then prints it to the screen? Mark for Review
(1) Points
for(int i=1;i<prices.length;i++)
System.out.println(prices[i]+5);
for(int i=0;i<prices.length;i++)
System.out.println(prices[1]+5);
for(int i=0;i<prices.length;i++)
System.out.println(prices[i]+5); (*)
System.out.println(prices[i]+5);
Incorrect Incorrect. Refer to Section 6 Lesson 1.
9. Which of the following declares and initializes a one dimensional array named words of size 3 so that all entries can be Strings? Mark for Review
(1) Points
String[] words={"Oracle","Academy"}];
String strings=new String[3];
String[] words={"Over","the","mountain"}; (*)
String[] words=new String[3];
Incorrect Incorrect. Refer to Section 6 Lesson 1.
10. What is the output of the following segment of code?
Mark for Review
(1) Points
7531 (*)
6
This code does not compile.
753
7766554433221
11. Which of the following declares and initializes a one dimensional array that can hold 5 Object reference types? Mark for Review
(1) Points
String[] array=String[4];
String[] array=new String[5];
Object[] array=new Object[4];
Object array=new Object[5]; (*)
Incorrect Incorrect. Refer to Section 6 Lesson 1.
12. The following array declaration is valid. True or false?
int k[] = new int[10]; Mark for Review
(1) Points
True (*)
False
Correct Correct
13. The following segment of code initializes a 2 dimensional array of references. True or false?
String[][] array={{"a", "b", "C"},{"a", "b", "c"}}; Mark for Review
(1) Points
True (*)
False
Correct Correct
14. What is the output of the following segment of code if the command line arguments are "a b c d e f"?
Mark for Review
(1) Points
1
3
This code doesn't compile.
6 (*)
5
Incorrect Incorrect. Refer to Section 6 Lesson 1.
15. Which of the following declares a one dimensional array named names of size 8 so that all entries can be Strings? Mark for Review
(1) Points
String names=new String[8];
String[] name=String[8];
String[] names=new String[8]; (*)
String[] name=new Strings[8];
Incorrect Incorrect. Refer to Section 6 Lesson 1.
Previous Page 3 of 3 Summary
1. Which of the following correctly matches the symbol with its function? Mark for Review
(1) Points
(Choose all correct answers)
== (two equal signs) compares the memory location of non-primitive objects. (*)
.equals() compares the value of non-primitive objects. (*)
= (single equals sign) compares the value of primitive types such as int or char.
== (two equal signs) compares the values of non-primitive objects.
== (two equal signs) compares values of primitive types such as int or char. (*)
Correct Correct
2. Suppose you misspell a method name when you call it in your program. Which of the following explains why this gives you an exception? Mark for Review
(1) Points
This will not give you an exception, it will give you an error when the program is compiled. (*)
Because the parameters of the method were not met.
Because the interpreter tries to read the method but when it finds the method you intended to use it crashes.
Because the interpreter does not recognize this method since it was never initialized, the correct spelling of the method was initialized.
Correct Correct
3. What exception message indicates that a variable may have been mispelled somewhere in the program? Mark for Review
(1) Points
variableName cannot be resolved to a variable (*)
method methodName(int) is undefined for the type className
Syntax error, insert ";" to complete statement
All of the above
Correct Correct
4. It is possible to throw and catch a second exception inside a catch block of code. True or false? Mark for Review
(1) Points
True (*)
False
Correct Correct
5. If an exception is thrown by a method, where can the catch for the exception be? Mark for Review
(1) Points
The catch can be in the method that threw the exception or in any other method that called the method that threw the exception. (*)
The catch must be in the method that threw the exception.
There does not need to be a catch in this situation.
The catch must be immediately after the throw.
Correct Correct
6. Which of the following declares and initializes a one dimensional array named words of size 10 so that all entries can be Strings? Mark for Review
(1) Points
String words=new String[10];
char words=new char[10];
String[] words=new String[10]; (*)
char[] words=new char[10];
Correct Correct
7. Which of the following declares a one dimensional array name scores of type int that can hold 14 values? Mark for Review
(1) Points
int score= new int[14];
int scores;
int[] scores=new int[14]; (*)
int[] scores=new scores int[14];
Correct Correct
8. What is the output of the following segment of code?
Mark for Review
(1) Points
This code doesn't compile.
312213
642
321123
642246 (*)
Correct Correct
9. Which of the following declares and initializes a one dimensional array named values of size 5 so that all entries contain 1? Mark for Review
(1) Points
int values[]={1,1,1,1,1,1};
int[] values={1};
int values={1,1,1,1,1};
int[] values={1,1,1,1,1}; (*)
Correct Correct
10. What is the output of the following segment of code if the command line arguments are "a b c d e f"?
Mark for Review
(1) Points
3
1
5
6 (*)
This code doesn't compile.
What is the output of the following segment of code?
Mark for Review
(1) Points
643432
262423242322
666666
1286864 (*)
This code does not compile.
Incorrect Incorrect. Refer to Section 6 Lesson 1.
12. The following creates a reference in memory named y that can refer to five different integers via an index. True or false?
int[] y = new int[5]; Mark for Review
(1) Points
True (*)
False
Correct Correct
13. Which of the following declares and initializes a one dimensional array named words of size 3 so that all entries can be Strings? Mark for Review
(1) Points
String[] words={"Oracle","Academy"}];
String strings=new String[3];
String[] words=new String[3];
String[] words={"Over","the","mountain"}; (*)
Correct Correct
14. The following creates a reference in memory named z that can refer to seven different doubles via an index. True or false?
double z[] = new double[7]; Mark for Review
(1) Points
True (*)
False
Correct Correct
15. Which of the following declares a one dimensional array named "score" of type int that can hold 9 values? Mark for Review
(1) Points
int score;
int score=new int[9];
int[] score;
int[] score=new int[9]; (*)
Incorrect Incorrect. Refer to Section 6 Lesson 1.
What is a hierarchy? Mark for Review
(1) Points
A programming philosophy that promotes simpler, more efficient coding by using existing code for new applications.
A structure that categorizes and organizes relationships among ideas and concepts of things with the most general at the top and the most specific at the bottom. (*)
A programming philosophy that promotes protecting data and hiding implementation in order to preserve the integrity of data and methods.
A keyword that allows subclasses to access methods, data, and constructors from their parent class.
Incorrect Incorrect. Refer to Section 7 Lesson 4.
2. Which of the following correctly describes the use of the keyword super? Mark for Review
(1) Points
A keyword that allows subclasses to access methods, data, and constructors from their parent class. (*)
A keyword that restricts access to only inside the same class.
A keyword that allows access from anywhere.
A keyword that signals the end of a program.
Incorrect Incorrect. Refer to Section 7 Lesson 4.
3. Methods are generally declared as public so other classes may use them. True or false? Mark for Review
(1) Points
True (*)
False
Correct Correct
4. Identify the error(s) in the class below. Choose all that apply.
Mark for Review
(1) Points
(Choose all correct answers)
No method named min is defined. (*)
The parameters must be the same for all methods with the same name.
Final cannot be used as an access modifier.
Two methods cannot have the same name.
Private cannot be used as an access modifier.
Incorrect Incorrect. Refer to Section 7 Lesson 2.
5. Which of the following is the correct definition of a parameter? Mark for Review
(1) Points
A variable in a method declaration that gets passed into the method. (*)
A way to call a method with a variable number of arguments using an elipse.
A keyword that specifies accessibility of code.
A type of access specifier.
It is used to assign initial values to instance variables of a class; the structure is very similar to that of a method.
Correct Correct
6. It is possible to have more than one constructor with the same name in a class, but they must have different parameters. True or false? Mark for Review
(1) Points
True (*)
False
Correct Correct
7. Static classes are designed as thread safe class instances. True or false? Mark for Review
(1) Points
True
False (*)
Incorrect Incorrect. Refer to Section 7 Lesson 3.
8. There is only one copy a static class variable in the JVM. True or false? Mark for Review
(1) Points
True (*)
False
Correct Correct
9. You can return an instance of a private class through a static method of a different class. True or false? Mark for Review
(1) Points
True
False (*)
Incorrect Incorrect. Refer to Section 7 Lesson 3.
10. Is there a difference between overriding a method and overloading a method? Mark for Review
(1) Points
No, they are the same.
Yes. Overriding is done within a single class and overloading is done through a series of superclasses and their subclasses.
Yes. Overriding is done in the subclass and allows for redefining a method inherited from the superclass and overloading is done within a class and allows for multiple methods with the same name. (*)
Yes. Overriding allows for the creation of an array of different object types and overloading restricts an array to only contain the same object types.
11. Abstract class cannot extend another abstract class. True or false? Mark for Review
(1) Points
True
False (*)
Correct Correct
12. Abstract classes cannot implement interfaces. True or false? Mark for Review
(1) Points
True
False (*)
Incorrect Incorrect. Refer to Section 7 Lesson 5.
13. The following statement compiles and executes. What can you say for sure?
submarine.dive(depth); Mark for Review
(1) Points
dive must be the name of an instance field.
submarine must be a method.
dive must be a method. (*)
The variable depth must be an int.
submarine must be the name of a class.
Incorrect Incorrect. Refer to Section 7 Lesson 1.
14. Instance variable names may only contain letters and digits. True or false? Mark for Review
(1) Points
True
False (*)
Incorrect Incorrect. Refer to Section 7 Lesson 1.
15. If the return type from a method is boolean then 2.5 is a valid return value. True or false? Mark for Review
(1) Points
True
False (*)
1. What operator do you use to call an object's constructor method and create a new object? Mark for Review
(1) Points
class
new (*)
instanceOf
Incorrect Incorrect. Refer to Section 7 Lesson 1.
2. Complete the sentence. A constructor... Mark for Review
(1) Points
must have the same name as the class it is declared within.
is used to create objects.
may be declared public.
is all of the above. (*)
Incorrect Incorrect. Refer to Section 7 Lesson 1.
3. The constructor of a class has the same name as the class. True or false? Mark for Review
(1) Points
True (*)
False
Correct Correct
4. Static classes can exist as stand alone classes. True or false? Mark for Review
(1) Points
True
False (*)
Incorrect Incorrect. Refer to Section 7 Lesson 3.
5. You can create static classes as independent classes. True or false? Mark for Review
(1) Points
True
False (*)
Correct Correct
6. Non-final static class variables should be private to prevent changes from other classes. True or false? Mark for Review
(1) Points
True (*)
False
1. Static methods can change instance variables at run-time. True or false? Mark for Review
(1) Points
True
False (*)
Incorrect Incorrect. Refer to Section 7 Lesson 3.
2. Non-final static class variables should be private to prevent changes from other classes. True or false? Mark for Review
(1) Points
True (*)
False
Correct Correct
3. Static classes can exist as stand alone classes. True or false? Mark for Review
(1) Points
True
False (*)
Correct Correct
4. Which of the following correctly defines a superclass (or parent class)? Mark for Review
(1) Points
The most specific class of a hierarchy system of classes.
A class that inherits methods and fields from a more general class.
A keyword that allows or restricts access to data and methods.
A class that passes down its methods to more specialized classes. (*)
Incorrect Incorrect. Refer to Section 7 Lesson 4.
5. Where should the constructor for a superclass be called? Mark for Review
(1) Points
Anywhere inside the subclass.
The super constructor does not need to be called inside the subclass.
Inside the main method of the subclass.
The last line in the constructor of the subclass.
The first line of the constructor in the subclass. (*)
6. Which is the most accurate description of the code reuse philosophy? Mark for Review
(1) Points
A programming philosophy that promotes having no concern about the security of code.
A programming philosophy that promotes simpler, more efficient coding by using existing code for new applications. (*)
A programming philosophy that promotes stealing your classmates' code.
A programming philosophy that promotes protecting data and hiding implementation in order to preserve the integrity of data and methods.
Incorrect Incorrect. Refer to Section 7 Lesson 4.
7. What is Polymorphism? Mark for Review
(1) Points
A way of redefining methods with the same return type and parameters.
The concept that a variable or reference can hold multiple types of objects. (*)
A way to create multiple methods with the same name but different parameters.
A class that cannot be initiated.
Incorrect Incorrect. Refer to Section 7 Lesson 5.
8. Abstract classes can be instantiated. True or false? Mark for Review
(1) Points
True
False (*)
Incorrect Incorrect. Refer to Section 7 Lesson 5.
9. What is the Java keyword final used for in a program? Mark for Review
(1) Points
It permits access to the class variables and methods from anywhere.
There is no such keyword in Java.
It permits redefining methods of a parent class inside the child class, with the same name, parameters, and return type.
It terminates the program.
It restricts a class from being extendable and restricts methods from being overridden. (*)
Incorrect Incorrect. Refer to Section 7 Lesson 5.
10. What is garbage collection in the context of Java? Mark for Review
(1) Points
The operating system periodically deletes all of the Java files available on the system.
Any package imported in a program and not used is automatically deleted.
When all references to an object are gone, the memory used by the object is automatically reclaimed. (*)
The JVM checks the output of any Java program and deletes anything that does not make sense.
Incorrect Incorrect. Refer to Section 7 Lesson 1.
11. What operator do you use to call an object's constructor method and create a new object? Mark for Review
(1) Points
+
instanceOf
new (*)
Incorrect Incorrect. Refer to Section 7 Lesson 1.
12. Which of the following creates an instance of the class below?
Mark for Review
(1) Points
ThisClass t;
ThisClass t=new ThisClass(5); (*)
ThisClass t=new ThisClass();
ThisClass t=new ThisClass(3,4);
Incorrect Incorrect. Refer to Section 7 Lesson 1.
13. How is it possible for overloading to work? Mark for Review
(1) Points
The code has to be declared as private.
Java Virtual Machine searches until it finds a constructor name and argument type match. (*)
The interpreter doesn't care what you name your constructors.
There is no such thing as overloading.
Incorrect Incorrect. Refer to Section 7 Lesson 2.
14. Cameron wishes to write a method that takes in two objects and returns the one with the greatest value. Is this possible? Mark for Review
(1) Points
No, it is not possible to return objects.
Yes, but he will have to use two different methods, one to take in the objects and the other to return an object.
Yes, methods can take objects in as parameters and can also return objects all within the same method. (*)
No, it is not possible to have objects as parameters or to return objects.
Incorrect Incorrect. Refer to Section 7 Lesson 2.
15. A team is working on a coding project. They desire that all portions of their code should have access to the classes that they write. What access modifier should be used for each class? Mark for Review
(1) Points
public (*)
protected
private
default
All of the above
Incorrect Incorrect. Refer to Section 7 Lesson 3.
7. Where should the constructor for a superclass be called? Mark for Review
(1) Points
The first line of the constructor in the subclass. (*)
The super constructor does not need to be called inside the subclass.
The last line in the constructor of the subclass.
Inside the main method of the subclass.
Anywhere inside the subclass.
Correct Correct
8. According to the following class declaration, runSpeed can be modified in class Cat. True or false
public class Tiger extends Cat{
public int runSpeed;
} Mark for Review
(1) Points
True
False (*)
Incorrect Incorrect. Refer to Section 7 Lesson 4.
9. Which of the following show the correct UML representation of the super class Planet and its subclass Earth? Mark for Review
(1) Points
(*)
None of the above.
Incorrect Incorrect. Refer to Section 7 Lesson 4.
10. Which of the following specifies accessibility to variables, methods, and classes? Mark for Review
(1) Points
Methods
Overload constructors
Parameters
Access modifiers (*)
11. Consider the following:
There is a method A that calls method B. Method B is a variable argument method.
With this, which of the following are true? Mark for Review
(1) Points
(Choose all correct answers)
Method A can invoke method B twice, each time with a different number of arguments. (*)
A compliler error will result since method B does not know how large an array to create when it is invoked by method A.
When invoked, method B creates an array to store some or all of the arguments passed to it from method A. (*)
All of the above.
Incorrect Incorrect. Refer to Section 7 Lesson 2.
12. Which of the following is the definition of a constructor? Mark for Review
(1) Points
A variable in a method declaration that gets passed into the method.
A keyword that specifies accessibility of code.
A special method that is used to assign initial values to instance variables in a class. (*)
A way to call a method with a variable number of arguments using an elipse.
Incorrect Incorrect. Refer to Section 7 Lesson 2.
13. Which of the following are true about abstract methods? Mark for Review
(1) Points
(Choose all correct answers)
They may contain implementation.
They cannot have a method body. (*)
They must be overridden in a non-abstract subclass. (*)
They must be overloaded.
They must be declared in an abstract class. (*)
Incorrect Incorrect. Refer to Section 7 Lesson 5.
14. Abstract class cannot extend another abstract class. True or false? Mark for Review
(1) Points
True
False (*)
Incorrect Incorrect. Refer to Section 7 Lesson 5.
15. If a class is immutable then it must be abstract. True or false? Mark for Review
(1) Points
True
False (*)
1. Which of the following demonstrates the correct way to create an applet Battlefield? Mark for Review
(1) Points
public Applet Battlefield{...}
public class Battlefield(Applet){...}
public class Battlefield extends Applet{...} (*)
public class Applet extends Battlefield{...}
Incorrect Incorrect. Refer to Section 7 Lesson 4.
2. Which of the following correctly defines a subclass (or child class)? Mark for Review
(1) Points
A class that inherits methods and fields from a more general class. (*)
A keyword that allows or restricts access to data and methods.
The most general class of a hierarchy system.
A class that passes down its methods to more specialized classes.
Correct Correct
3. What is encapsulation? Mark for Review
(1) Points
A programming philosophy that promotes simpler, more efficient coding by using exiting code for new applications.
A structure that categorizes and organizes relationships among ideas, concepts of things with the most general at the top and the most specific at the bottom.
A keyword that allows or restricts access to data and methods.
A programming philosophy that promotes protecting data and hiding implementation in order to preserve the integrity of data and methods. (*)
Incorrect Incorrect. Refer to Section 7 Lesson 4.
4. What does it mean to override a method? Mark for Review
(1) Points
It restricts the privacy of the method to only be accessible from inside the same class.
It is a way to create multiple methods with the same name but different parameters.
It allows an array to contain different object types.
It is a way of redefining methods of a parent class inside the child class, with the same name, parameters, and return type. (*)
Incorrect Incorrect. Refer to Section 7 Lesson 5.
5. Abstract class cannot extend another abstract class. True or false? Mark for Review
(1) Points
True
False (*)
6. What is Polymorphism? Mark for Review
(1) Points
A way of redefining methods with the same return type and parameters.
The concept that a variable or reference can hold multiple types of objects. (*)
A way to create multiple methods with the same name but different parameters.
A class that cannot be initiated.
Incorrect Incorrect. Refer to Section 7 Lesson 5.
7. Static methods can write to class variables. True or false? Mark for Review
(1) Points
True (*)
False
Correct Correct
8. Non-final static class variables should be private to prevent changes from other classes. True or false? Mark for Review
(1) Points
True (*)
False
Correct Correct
9. You can assign new values to static variables by prefacing them with the this keyword and a dot or period. True or false? Mark for Review
(1) Points
True (*)
False
Correct Correct
10. You are assigned to write a method that compares two objects of type Career. One requirement of your assignment is to have your method compare the "greatestPossibleSalary" instance data of Career objects. The "greatestPossibleSalary" field is data type int.
What would be the best return type from your compare method? Mark for Review
(1) Points
Career, because if it returns the highest paying Career object it will be able to use the same method later to compare other aspects of Career objects. (*)
Integer, because it is the easiest to code with.
Array, because it can store the most information.
String, because is should return a string of the name of the career that is highest paying because none of the other information of the career matters.
Incorrect Incorrect. Refer to Section 7 Lesson 2.
11. It is possible to overload a method that is not a constructor. True or False? Mark for Review
(1) Points
True (*)
False
Correct Correct
12. How is it possible for overloading to work? Mark for Review
(1) Points
The interpreter doesn't care what you name your constructors.
Java Virtual Machine searches until it finds a constructor name and argument type match. (*)
There is no such thing as overloading.
The code has to be declared as private.
Correct Correct
13. The return value of a method can only be a primitive type and not an object. True or false? Mark for Review
(1) Points
True
False (*)
Incorrect Incorrect. Refer to Section 7 Lesson 1.
14. Consider:
public class MyClass{
public MyClass()
{/*code*/}
// more code...}
To instantiate MyClass, what would you write? Mark for Review
(1) Points
MyClass m = new MyClass;
MyClass m = new MyClass(); (*)
MyClass m = MyClass;
MyClass m = MyClass();
Incorrect Incorrect. Refer to Section 7 Lesson 1.
15. The following statement compiles and executes. What can you say for sure?
submarine.dive(depth); Mark for Review
(1) Points
submarine must be the name of a class.
submarine must be a method.
dive must be a method. (*)
dive must be the name of an instance field.
The variable depth must be an int.
Incorrect Incorrect. Refer to Section 7 Lesson 1.
1. Methods are generally declared as public so other classes may use them. True or false? Mark for Review
(1) Points
True (*)
False
Correct Correct
2. Which of the following correctly describes the use of the keyword super? Mark for Review
(1) Points
A keyword that signals the end of a program.
A keyword that allows subclasses to access methods, data, and constructors from their parent class. (*)
A keyword that allows access from anywhere.
A keyword that restricts access to only inside the same class.
Incorrect Incorrect. Refer to Section 7 Lesson 4.
3. What does it mean to inherit a class? Mark for Review
(1) Points
The subclass (or child class) gains access to any non-private methods and variables of the superclass (or parent class). (*)
A way of organizing the hierarchy of classes.
The access specifier has been set to private.
Extending a method from a superclass.
Correct Correct
4. A team is working on a coding project. They desire that all portions of their code should have access to the classes that they write. What access modifier should be used for each class? Mark for Review
(1) Points
public (*)
protected
private
default
All of the above
Correct Correct
5. What type(s) would work for a variable argument method? Mark for Review
(1) Points
(Choose all correct answers)
Integers, Strings, and Booleans (*)
Constructors
Arrays (*)
Objects (*)
All of the above
6. You are assigned to write a method that compares two objects of type Career. One requirement of your assignment is to have your method compare the "greatestPossibleSalary" instance data of Career objects. The "greatestPossibleSalary" field is data type int.
What would be the best return type from your compare method? Mark for Review
(1) Points
String, because is should return a string of the name of the career that is highest paying because none of the other information of the career matters.
Integer, because it is the easiest to code with.
Career, because if it returns the highest paying Career object it will be able to use the same method later to compare other aspects of Career objects. (*)
Array, because it can store the most information.
Incorrect Incorrect. Refer to Section 7 Lesson 2.
7. Consider
public class YourClass{
public YourClass(int i)
{/*code*/}
// more code...}
To instantiate YourClass, what would you write? Mark for Review
(1) Points
YourClass y = new YourClass();
YourClass y = new YourClass(3); (*)
YourClass y = YourClass(3);
YourClass y = YourClass();
None of the above.
Incorrect Incorrect. Refer to Section 7 Lesson 1.
8. What value will be returned when the setValue method is called?
Mark for Review
(1) Points
36
35
37 (*)
38
Incorrect Incorrect. Refer to Section 7 Lesson 1.
9. Which of the following calls the method moveUp in the class below:
Mark for Review
(1) Points
Puzzle p=new Puzzle(); p.moveUp(3,4,5);
PuzzlePiece p=new PuzzlePiece(); p.moveUp(3,4,5);
PuzzlePiece p=new PuzzlePiece(); p.moveUp(3,4); (*)
Puzzle p=new Puzzle(); p.moveUp(3,4);
Incorrect Incorrect. Refer to Section 7 Lesson 1.
10. There is only one copy a static class variable in the JVM. True or false? Mark for Review
(1) Points
True (*)
False
11. Which of the following statements about static methods is true? Mark for Review
(1) Points
They exist once in each instance.
They can be overridden by a subclass.
They cannot access static variables declared outside the method.
They can access any instance variable.
They exist once per class. (*)
Incorrect Incorrect. Refer to Section 7 Lesson 3.
12. Static methods can read instance variables. True or false? Mark for Review
(1) Points
True
False (*)
Incorrect Incorrect. Refer to Section 7 Lesson 3.
13. What allows Java to correctly and automatically determine which method to invoke based on the type of object being referred to at the time the method is called? Mark for Review
(1) Points
Dynamic Method Dispatch (*)
Polymorphism
Abstract classes
Inheritance
Correct Correct
14. Identify the step (s) in creating a Triangle Applet that displays two triangles. Mark for Review
(1) Points
(Choose all correct answers)
Run and compile your code. (*)
Draw the triangle using the inherited fillPolygon method. (*)
Draw the 2nd triangle using the inherited fillPolygon method. (*)
Extend Applet class to inherit all methods including paint. (*)
Override the paint method to include the triangles. (*)
Incorrect Incorrect. Refer to Section 7 Lesson 5.
15. Is there a difference between overriding a method and overloading a method? Mark for Review
(1) Points
Yes. Overriding allows for the creation of an array of different object types and overloading restricts an array to only contain the same object types.
No, they are the same.
Yes. Overriding is done in the subclass and allows for redefining a method inherited from the superclass and overloading is done within a class and allows for multiple methods with the same name. (*)
Yes. Overriding is done within a single class and overloading is done through a series of superclasses and their subclasses.
3 komentar
Kuncinya lengkap bgt xD
terimakasih bapak yg telah membantu. top markotop, walaupun masih ada kesalahan 1 1 jawabannya, tapi yg penting lulus.
will omit your great writing due to this problem.
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