Section 3 Oracle Java Fundamental Quiz Section 3 - Quiz 1 L1-L5 (Answer all questions in this section) 1. From your Greenfoot lessons, Which of the following statements is most correct? My program is complete when I add music to it. My program is complete when it runs and I've tested the code. ( *) My program is complete when I add images to it. My program is complete when it compiles. 2.
Which of the following Java syntax is used to correctly create a Bee subclass? private class extends Bee private Bee extends World public class Bee extends World private class extends Actor public class Bee extends Animal (*)
3. What does an instance of the World class do? Mark for Review (1) Points Provide the superclass for acting objects. Provide the source code for instances. Provide the background scenery for the scenario. (*) Provide the acting objects for the scenario. 4. In Greenfoot, after a subclass is created, what has to occur before instances can be added to the scenario? Mark for Review (1) Points Creation of an instance Creation of source code Editing of source code Compilation (*) 5. In Greenfoot, the class holds the general attributes of an instance, such as the methods it inherits. True or false? Mark for Review (1) Points True (*) False 6. In Greenfoot, the body of the method is located in between which of the following characters? Mark for Review (1) Points Square brackets [ ] Curly brackets { } (*) Asterisks ** Parnetheses ( ) 7. In Greenfoot, the move method expects what type of information in its parameters? Mark for Review (1) Points
Degrees to turn Integer of steps to move forward (*) True or false response String statement 8. A variable is also known as a ____________. (1) Points Instance Syntax Field (*) Method Class
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9. Using the Greenfoot IDE, only five instances can be added to a scenario. True or false? Mark for Review (1) Points True False (*) 10. From your Greenfoot lessons, when does an if-else statement execute it's second code segment? Mark for Review (1) Points If a condition is true. After the first code segment is executed. When an instance is created. When a random number is less than 10. If a condition is false. (*) 11. In Greenfoot, which of the following is the correct notation for calling a method for an instance of a class? Mark for Review (1) Points Method-name.object-name(parameters); Method-name.object-name; object-name.method-name(parameters); (*) class-name.method-name(parameters); 12. Which of the following Greenfoot methods returns a random number between 0, up to and including 10,000? Mark for Review (1) Points Greenfoot.getRandomNumber(0-10,000) Greenfoot.getRandomNumber(9,999) Greenfoot.getRandomNumber(10,000) Greenfoot.getRandomNumber(10,001) (*) 13. Read the following method signature. Using your Greenfoot experience, what does this method do? public static int getRandomNumber (int limit) Mark for Review (1) Points Returns a random number between zero and the parameter limit. (*)
Returns a random number for instances in the animal class only. Returns a random coordinate position in the world. Returns a random number less than 10. Correct Correct 14. From your Greenfoot lessons, where do you review a class's inherited methods? Mark for Review (1) Points Inspector Act method If-statement Documentation (*) 15. The list below displays components of the Greenfoot source code editor except one. Which one should be removed? Mark for Review (1) Points Class description Comments Instance creator (*) Documentation Method body 1. In Greenfoot, only 10 methods can be written for each class in the Code editor. True or false? Mark for Review (1) Points True False (*) 2. From your Greenfoot lessons, where do you review a class's inherited methods? Mark for Review (1) Points Act method Inspector Documentation (*) If-statement 3. In Greenfoot, the turn method expects what type of information in its parameters? Mark for Review (1) Points Parameter void True or false response Integer of steps to move forward Degrees to turn (*) String statement 4. In Greenfoot, methods can be called in the act method. When the Act button is clicked in the environment, the methods in the method body of the act method are executed. True or false? Mark for Review (1) Points True (*)
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5. Using the Greenfoot IDE, only five instances can be added to a scenario. True or false? Mark for Review (1) Points True False (*) 6. In Greenfoot, the instance has a source code editor. True or false? Mark for Review (1) Points True False (*) 7. In Greenfoot, the origin of the world coordinate system (0,0) starts in the center of the world. True or false? Mark for Review (1) Points True False (*) 8. From your Greenfoot lessons, classes can only use the methods they have inherited. They cannot use methods from other classes. True or false? Mark for Review (1) Points True False (*) 9. The list below displays characteristics of a Greenfoot world constructor, except for one. Which one should be removed? Mark for Review (1) Points Has no return type. Has a void return type. (*) Executed automatically when a new instance of the class is created. Defines the instance's size and resolution. Has the same name as the name of the class. 10. What does the following Greenfoot programming statement tell the class to do? if (Greenfoot.getRandomNumber(100) < 6) { turn(18); } Mark for Review (1) Points Turn 6 degrees, then turn 18 degrees. If a random number is returned that is greater than 6, turn 18 degrees. If a random number is returned that is less than 6, turn 18 degrees. (*) If a random number is returned that is less than 6, move 18 steps. 11. In Greenfoot, you will not receive an error message if your code is incorrect. It will simply not work, and you will have to determine why the code doesn't work. True or false? Mark for Review (1) Points True False (*)
12. In Greenfoot, what happens to an instance when the Act button is clicked in the environment? Mark for Review (1) Points The class executes all of the programming statements in their instance's act method two times until the scenario is stopped. The instance executes all of the programming statements in their class's act method once. (*) The instance executes all of the programming statements i n their class's act method two times until the scenario is stopped. The instance executes all of the programming statements in their class's act method repeatedly until the scenario is stopped. Only one instance moves until the pause button is clicked. 13. In Greenfoot, after a subclass is created, what has to occur before instances can be added to the scenario? Mark for Review (1) Points Creation of an instance Editing of source code Creation of source code Compilation (*) 14. In Greenfoot, a subclass is created by right-clicking on a superclass. True or false? Mark for Review (1) Points True (*) False 15. Which of the following Java syntax is used to correctly create a Bee subclass? Mark for Review (1) Points private class extends Actor private Bee extends World public class Bee extends World public class Bee extends Animal (*) private class extends Bee 1. Which of the following is an incorrectly written programming statement? Mark for Review (1) Points move(2); move(): (*) turn(25); turn(2); 2. In Greenfoot, the move method expects what type of information in its parameters? Mark for Review (1) Points Degrees to turn True or false response Integer of steps to move forward (*)
String statement 3. In Greenfoot, the body of the method is located in between which of the following characters? Mark for Review (1) Points Square brackets [ ] Curly brackets { } (*) Asterisks ** Parnetheses ( ) 4. In Greenfoot, the turn method expects what type of information in its parameters? Mark for Review (1) Points String statement Degrees to turn (*) Parameter void True or false response Integer of steps to move forward 5. An instance variable can be saved and accessed later, even if the instance no longer exists. True or false? Mark for Review (1) Points True False (*) 6. In Greenfoot, which of the following methods return the world that the instance lives in? Mark for Review (1) Points World getWorld() (*) World getClass() getXY() getRotation() 7. An if-statement requires which type of information returned from the condition? Mark for Review (1) Points Method Action True or false (*) Integer 8. In Greenfoot, the class holds the general attributes of an instance, such as the methods it inherits. True or false? Mark for Review (1) Points True (*) False 9. In Greenfoot, after a subclass is created, what has to occur before instances can be added to the scenario? Mark for Review (1) Points
Editing of source code Compilation (*) Creation of source code Creation of an instance 10. In Greenfoot, a subclass is a specialization of a superclass. True or false? Review (1) Points True (*) False
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11. In Greenfoot, what happens to an instance when the Act button is clicked in the environment? Mark for Review (1) Points Only one instance moves until the pause button is clicked. The instance executes all of the programming statements i n their class's act method once. (*) The class executes all of the programming statements in their instance's act method two times until the scenario is stopped. The instance executes all of the programming statements i n their class's act method two times until the scenario is stopped. The instance executes all of the programming statements in their class's act method repeatedly until the scenario is stopped. 12. In Greenfoot you can use comparison operators to compare a variable to a random number. True or false? Mark for Review (1) Points True (*) False 13. From your Greenfoot lessons, dot notation allows you to use a method from a different class, if the class you are programming does not possess the method. True or false? Mark for Review (1) Points True (*) False 14. From your Greenfoot lessons, which type of constructor can be used to automate creation of Actor instances? Mark for Review (1) Points World (*) Vector Actor Animal 15. The first step to executing an if-else statement is to:____________. Mark for Review (1) Points Evaluate the class Evaluate the condition (*) Execute the if statement
Execute the else statement 1. Which actor method is used to detect a simple collision? (1) Points isTouching() (*) isCollision() isInContactWith() hasCollided() hasTouched()
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2. In Greenfoot, defined methods must be used immediately. True or false? Mark for Review (1) Points True False (*) 3. Which one of the following can be used to detect when 2 actors collide? Review (1) Points isTouching() (*) isCollision() hasCollided() isContact()
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4. In Greenfoot when you use the method to retrieve input from the user, the scenario will continue to run in the background? Mark for Review (1) Points True False (*) 5. Greenfoot has tools to record sound. True or false? Mark for Review (1) Points True (*) False 6. What type of parameter does the keyDown method expect? Mark for Review (1) Points The name of the class that will use the key. The name of the sound file to play when the key is pressed. The password that will protect the class. The name of the key to press on the keyboard. (*) 7. In Greenfoot the showText() method belongs to which class? (1) Points There is no such method. Actor Greenfoot World (*)
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8. Use your Greenfoot knowledge to answer the question: Where are defined variables typically entered in a class's source code? Mark for Review (1) Points After the constructors and methods in the source code. At the top of the source code, before the constructors and methods. (*) Between the constructors and methods in the source code. In the defined method in the source code. 9. Where can we review the available classes and methods in Greenfoot, including the stop method? Mark for Review (1) Points Greenfoot Application Programmers' Interface (API) (*) Class menu Object menu Class Application Programmers' Interface (API) 10. In Java what is casting? Mark for Review (1) Points Casting is when we remove an object from the world Casting is when we want to tell the java compiler that a class we are accessing is really another type of class (*) Casting is when we reset the state of an instance. Casting is when we change the coordinates of an actor 11. Use your Greenfoot knowldege: If an Actor class Fly has a variable defined to store the current speed, which of the following statements would successfull y add a Fly and define the current speed as 2? Mark for Review (1) Points addObject (new Fly(), 2, 150, 150); addObject (new Fly(), 150, 150); addObject (new Fly(2, 90), 150, 150); addObject (new Fly(2), 150, 150); (*) 12. Use your Greenfoot knowldege: Abstraction occurs in many different ways in programming. True or false? Mark for Review (1) Points True (*) False 13. In Greenfoot, which statement is a correct example of string concatenation? Mark for Review (1) Points bee.setImage("bee" + i + ".png"); (*) bee.setImage("bee.png"); Bee bee = new Bee(image1); bee.setImage("bee" - "I" - ".png");
14. From your Greenfoot lessons, which symbol represents string concatenation? Mark for Review (1) Points Symbol = Symbol & Symbol + (*) Symbol < 15. From your Greenfoot lessons, when do infinite loops occur? (1) Points When the end to the act method isn't established. Only in while loops. When the end to the code isn't established. (*) When the loop is executed.
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1. From your Greenfoot lessons, how do you call a defined method? Mark for Review (1) Points Write the method in the Actor class. Call the method from the act method. (*) Write the method in the World superclass. Write the method in the documentation. Write the method in the instance. 2. Which one of the following can be used to detect when 2 actors collide? Review (1) Points isContact() hasCollided() isCollision() isTouching() (*) 3. Which actor method is used to detect a simple collision? (1) Points hasTouched() hasCollided() isCollision() isInContactWith() isTouching() (*)
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4. Greenfoot has tools to record sound. True or false? Mark for Review (1) Points True (*) False 5. In Greenfoot, what type of parameter does the isKeyDown method expect? Mark for Review (1) Points Method Integer Boolean
String (*) 6. In Greenfoot when you use the method to retrieve input from the user, the scenario will continue to run in the background? Mark for Review (1) Points True False (*) 7. In Greenfoot, a defined variable is a variable that is defined in an instance. True or false? Mark for Review (1) Points True False (*) 8. When you re-initialize a scenario, Greenfoot automatically displays an instance of the World subclass in the scenario. True or false? Mark for Review (1) Points True (*) False 9. Which of the following answers have the correct syntax for declaring a class variable in Greenfoot? Mark for Review (1) Points (Choose all correct answers) private variable-type variable-name; (*) public variable-type variable-name; (*) private variable-name, variable-type; public variable-name variable type; 10. In Greenfoot modifying an actors constructor to accept an initial speed is a form of abstraction? Mark for Review (1) Points True (*) False 11. In Greenfoot, you will never have to cast as we only ever use 2 classes - World and Actor. Mark for Review (1) Points True False (*) 12. From your Greenfoot lessons, which one of the following is an example of when an abstraction technique is used? Mark for Review (1) Points Initialising a variable Adding a property to an instance Passing a paramater in a constructor to set an initial speed. (*) Adding a property to a Class 13.
Which of the following Greenfoot logic operators represents "not"? Mark for Review
(1) Points && & = ! (*) 14. In Greenfoot, which statement is a correct example of string concatenation? Mark for Review (1) Points bee.setImage("bee.png"); Bee bee = new Bee(image1); bee.setImage("bee" + i + ".png"); (*) bee.setImage("bee" - "I" - ".png"); 15. How would the following sentence be written in Greenfoot source code? If Bee is turning, and the keyboard key "d" is down... Mark for Review (1) Points if (isTurning && Greenfoot.isKeyDown("d") ) (*) if (!isTurning && Greenfoot.isKeyDown("d") ) if (&&isTurning ! Greenfoot.isKeyDown("d") ) if (!Greenfoot.isKeyDown && isTurning("d") ) 1.
In reference to Greenfoot, if the following method was defined in a superclass,
public void turnAtEdge(){ ... } all subclasses of the superclass will inherit the method. True or false? Mark for Review (1) Points True (*) False 2. In Greenfoot a collision is when 2 actors touch? (1) Points True (*) False
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3. Defined methods are methods that are only created by the Greenfoot development team? Mark for Review (1) Points True False (*) 4. Greenfoot has tools to record sound. True or false? Mark for Review (1) Points True (*) False
5. In Greenfoot, which method checks if a key on the keyboard has been pressed? Mark for Review (1) Points keyPress method isKeyDown method (*) isKeyUp method keyClick method 6. From your Greenfoot lessons, the isKeyDown method is located in which class? Mark for Review (1) Points Greenfoot (*) GreenfootImage World Actor 7. In Greenfoot, the == operator is used to test if two values are equal. True or false? Mark for Review (1) Points True (*) False 8. In Greenfoot, a constructor has a void return type. True or false? (1) Points True False (*)
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9. Which class holds the method that ends a Greenfoot game? Mark for Review (1) Points Greenfoot (*) GreenfootImage Class Actor 10. Abstraction occurs in many different ways in programming. True or false? Mark for Review (1) Points True (*) False 11. In Java what is casting? Mark for Review (1) Points When you remove an object instance. When you reset an object instance. When you take an Object of one particular type and turn it into another Objec t type. (*) Casting is not possible in Java. 12. From your Greenfoot lessons, which one of the following is an example of when an abstraction technique is used? Mark for Review
(1) Points Adding a property to an instance Adding a property to a Class Initialising a variable Passing a paramater in a constructor to set an initial speed. (*) 13. In Greenfoot, what is a common letter used for the loop variable? Mark for Review (1) Points A I (*) X Y 14. In the Greenfoot IDE, what does the AND operator (&&) do? Mark for Review (1) Points Compares two boolean variables or expressions and returns a result that is true if either of its operands are true. Compares two boolean values, and returns a boolean value which is true if and only if both of its operands are true. (*) Compares two boolean values, and returns a boolean value which is tr ue if and only if one of its operands are true. Compares two boolean values and returns a boolean value which is true if either one of the operands is true. 15. In Greenfoot, string concatenation reduces the number of redundant characters or phrases you need to type into each array. True or false? Mark for Review (1) Points True (*) False 1. In Greenfoot, defined methods must be used immediately. True or false? Mark for Review (1) Points True False (*) 2. Use your Greenfoot knowledge to answer the question. One reason to write a defined method in a class is to make it easier to read. True or false? Mark for Review (1) Points True (*) False 3. In Greenfoot, a way to have all subclasses of a superclass inherit a method is by adding the method to the superclass. True or false? Mark for Review (1) Points True (*) False
4. In Greenfoot, what type of parameter does the isKeyDown method expect? Mark for Review (1) Points Integer String (*) Method Boolean 5. In Greenfoot, which method checks if a key on the keyboard has been pressed? Mark for Review (1) Points keyClick method keyPress method isKeyUp method isKeyDown method (*) 6. What type of parameter does the keyDown method expect? Mark for Review (1) Points The name of the key to press on the keyboard. (*) The password that will protect the class. The name of the sound file to play when the key is pressed. The name of the class that will use the key. 7. In Greenfoot, an if-statement is used to alternate between displaying two images in an instance. True or false? Mark for Review (1) Points True (*) False 8. The GreenfootImage class enables Greenfoot actors to maintain their visible image by holding an object of type GreenfootImage. True or false? Mark for Review (1) Points True (*) False 9. In Greenfoot, what is the purpose of the variable type? (1) Points Defines the access specifier used with the variable. Defines the instance that the variable is associated with. Defines which class the variable is associated with. Defines what kind of data to store in the variable. (*)
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10. In Greenfoot, you will never have to cast as we only ever use 2 classes - World and Actor. Mark for Review (1) Points True False (*) 11.
In Java what is casting?
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(1) Points When you take an Object of one particular type and turn it into another Object type. (*) Casting is not possible in Java. When you remove an object instance. When you reset an object instance. 12. Use your Greenfoot knowldege: If an Actor class Fly has a variable defined to store the current speed, which of the following statements would successfull y add a Fly and define the current speed as 2? Mark for Review (1) Points addObject (new Fly(), 2, 150, 150); addObject (new Fly(2, 90), 150, 150); addObject (new Fly(2), 150, 150); (*) addObject (new Fly(), 150, 150); 13. In Greenfoot, what happens if the end to a while loop isn't established? Review (1) Points The code will execute once and then stop, due to controls in Greenf oot. The code will not execute. The code will prompt you to enter a loop counter. The code will keep executing and will never stop. (*) 14. In the Greenfoot IDE, what does the AND operator (&&) do? (1) Points
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Compares two boolean values and returns a boolean value which is true if either one of the operands is true. Compares two boolean variables or expressions and returns a result that is true if either of its operands are true. Compares two boolean values, and returns a boolean value which is true if and only if one of its operands are true. Compares two boolean values, and returns a boolean value which is true i f and only if both of its operands are true. (*) 15. If an end to a while loop is not established, what happens? Mark for Review (1) Points The code stops after 20 executions. The code stops after 10 executions. The condition becomes false after one minute of executions. The code executes and does not stop. (*)