Java Midterm exam

Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer. Section 4 (Answer all questions in this section) 1The following code is an example of instantiating a String object: . String str = String( "Hello" );

Mark for Review (1) Points

True or false? True False (*) Correct 2The following program prints "Not Equal": .


True or false? True (*) False Correct 3Consider the following code snippet. .

What is printed?


Cayrbniz CayrbnizCayrbniz yr (*) ay ArrayIndexOutofBoundsException is thrown Correct 4What will the following code segment output? . String s="\\\n\"\n\\\n\""; System.out.println(s);


\" \" ""\ "" \ "" \ " \ " (*) " \ " \ " " Correct 5Given the code . String s1 = "abcdef"; String s2 = "abcdef"; String s3 = new String(s1); Which of the following would equate to false? s1 == s2 s1 = s2 s3 == s1 (*) s1.equals(s2) s3.equals(s1)


Correct Section 4 (Answer all questions in this section) 6. The following defines an import keyword:


Defines where this class lives relative to other classes, and provides a level of access control. Provides the compiler information that identifies outside classes used within the current class. (*) Precedes the name of the class. Correct 7. Which of the following defines an object class?


Contains a main method and other static methods. Contains classes that define objects. (*) Contains a main method, a package, static methods, and classes that define objects. None of the above. Correct 8. Which of the following is not a legal name for a variable?


2bad (*) zero theLastValueButONe year2000 Correct 9. Which of the following is the name of a Java primitive data type?


Object Rectangle double (*) String Correct 10.A workspace can not have more than one stored projects. True or false?


True False (*) Correct Section 4 (Answer all questions in this section) 11.Multiple windows are used when more than one file is open in the edit area. True or False?


True False (*) Incorrect. Refer to Section 4 Lesson 1. 12.What symbols are required for a compiler to ignore a comment?


// (*) /* */ /*/ Correct 13.You need to _______________ Java code to generate a .class file

Collect


Compile (*) Package Assemble Correct 14.What is the purpose of the Eclipse Editor Area and Views?


(Choose all correct answers) To modify elements. (*) To navigate a hierarchy of information. (*) To choose the file system location to delete a file. Correct

Section 5 (Answer all questions in this section) 15.switch statements work on all input types including, but not limited to, int, char, and String. True or false?


True False (*) Correct Section 5 (Answer all questions in this section) 16.How would you use the ternary operator to rewrite this if statement? if (gender == "female") System.out.print("Ms."); else System.out.print("Mr."); System.out.print( (gender == "female") ? "Mr." : "Ms." ); System.out.print( (gender == "female") ? "Ms." : "Mr." ); (*) (gender == "female") ? "Mr." : "Ms." ; (gender == "female") ? "Ms." : "Mr." ;


Incorrect. Refer to Section 5 Lesson 1. 17.Determine whether this boolean expression evaluates to true or false: !(3<4&&6>6||6<=6&&7-2==6)


True (*) False Incorrect. Refer to Section 5 Lesson 1. 18.In the code fragment below, the syntax for the for loop's initialization is correct. True or false? public class ForLoop { public static void main (String args[]) { for ((int 1=10) (i<20) (i++))
{System.out.Println ("i: "+i); } } }


True False (*) Incorrect. Refer to Section 5 Lesson 2. 19.When the for loop condition statement is met the construct is exited. True or false?


True False (*) Correct 20.Which of the following is true about a do-while loop?

It is a post-test loop. It is a modified while loop that allows the program to run through the loop once before testing the boolean condition. It continues looping until the condition becomes false.


All of the above. (*) Correct Section 6 (Answer all questions in this section) 21Which of the following statements add all of the elements of the one . dimensional array prices, and then prints the sum to the screen?


int total = 0; for(int i = 0; i total+=prices[i]; int total = 0; for(int i = 0; i total+=prices[i]; System.out.println(total); (*) 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); Correct 22What is the output of the following segment of code if the command line . arguments are "a b c d e f g"?

f e (*) c d This code doesn't compile. Incorrect. Refer to Section 6 Lesson 1.


23What is the output of the following segment of code? .


321123 642 642246 (*) 312213 This code doesn't compile. Correct 24The following segment of code initializes a 2 dimensional array of . primitive data types. True or false? double[][] a=new double[4][5];


True (*) False Correct 25What is wrong with this code? .

It is missing a semicolon. It does not compile. (*) It gives you an out of bounds exception. There is nothing wrong with this code. Correct Section 6 (Answer all questions in this section)


26.Selection sort is a sorting algorithm that involves finding the minimum value in the list, swapping it with the value in the first position, and repeating these steps for the remainder of the list. True or false?


True (*) False Correct 27.Of the options below, what is the fastest run-time?


n n^2 lg(n) (*) n*lg(n) Correct 28.Bubble Sort is a sorting algorithm that involves swapping the smallest value into the first index, finding the next smallest value and swapping it into the next index and so on until the array is sorted. True or false?


True False (*) Correct 29.Why might a sequential search be inefficient?

It utilizes the "divide and conquer" method, which makes the algorithm more error prone. It requires incrementing through the entire array in the worst case, which is inefficient on large data sets. (*) It involves looping through the array multiple times before finding the value, which is inefficient on large data sets. It is never inefficient. Correct


Section 7 (Answer all questions in this section) 30.Which of the following is the correct way to code a method with a return type an object Automobile?


Automobile upgrade(String carA){ carA="Turbo"; return carA;} Automobile upgrade(Automobile carA){ carA.setTurbo("yes"); return carA;} (*) String upgrade(String carA){ carA="Turbo"; return carA;} upgrade(Automobile carA) Automobile{ carA.setTurbo("yes"); return carA;} None of the above. It is not possible to return an object. Correct Section 7 (Answer all questions in this section) 31.Which of the following specifies accessibility to variables, methods, and classes?


Methods Parameters Overload constructors Access modifiers (*) Incorrect. Refer to Section 7 Lesson 2. 32.Which of the following are access modifiers?

(Choose all correct answers) protected (*) public (*)


secured default (no access modifier) (*) private (*) Incorrect. Refer to Section 7 Lesson 2. 33.Which of the following is the definition of a constructor?


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. A variable in a method declaration that gets passed into the method. Correct 34.Which segment of code correctly defines a method that contains two objects of class Tree as parameters?


void bloom(Tree pine, Tree oak) {//code here }; (*) Tree bloom (pine, oak) {//code here }; void bloom, Tree pine, Tree oak {//code here }; None of the above, objects cannot be passed as parameters. Incorrect. Refer to Section 7 Lesson 2. 35.What is Polymorphism?

A way of redefining methods with the same return type and parameters. A way to create multiple methods with the same name but different parameters. A class that cannot be initiated. The concept that a variable or reference can hold multiple types of objects. (*) Correct Section 7 (Answer all questions in this section)


36.Identify the correct way to declare an abstract class.


abstract public class ClassName{...} public abstract ClassName(...) public class abstract ClassName(...) public abstract class ClassName{...} (*) Correct 37.Abstract classes cannot implement interfaces. True or false?


True False (*) Correct 38.A linear recursion requires the method to call which direction?


Forward Backward (*) Both forward and backward None of the above Correct 39.There is only one copy a static class variable in the JVM. True or false?


True (*) False Correct 40.Static methods can't change any class variable values at run-time. True or false? True False (*) Correct


Section 7 (Answer all questions in this section) 4In Java, an instance field referenced using the this keyword generates a 1.compilation error. True or false?


True False (*) Correct 4A constructor is used to create objects. True or false? 2.


True (*) False Correct 4A constructor must have the same name as the class where it is declared. 3.True or false?


True (*) False Correct 4Identify the driver class that correctly initializes employees Jane and 4.Brandon. The Employee class is below. public class Employee { private String name; private int age; private double salary; public Employee(String n, int a, double s) { name = n; age = a; salary = s; } //methods for this class would go here }


public class driver_class { public static void main(String[] args) { Employee Jane = new Employee("Jane", 48, 35.00); Employee Brandon = new Employee("Brandon", 36, 20.00); } } (*) public class driver_class { public static void main(String[] args) { Employee("Jane", 48, 35.00); Employee("Brandon", 36, 20.00); } } public class driver_class { public Employee{ Jane = new Employee("Jane", 48, 35.00); Brandon = new Employee("Brandon", 36, 20.00); } } public class Employee { public class driver-class{ Employee Jane = new Employee(); Employee Brandon = new Employee(); } } Incorrect. Refer to Section 7 Lesson 1. 4Which of the following creates a method that compiles with no errors in 5.the class?


(*)

All of the above. None of the above. Incorrect. Refer to Section 7 Lesson 1. Section 7 (Answer all questions in this section) 46.The following code creates an object of type Horse: Whale a=new Whale();


True False (*) Correct 47.Which of the following is the correct way to call an overriden method needOil() of a super class Robot in a subclass SqueakyRobot?


Robot.needOil(SqueakyRobot); SqueakyRobot.needOil(); super.needOil(); (*) needOil(Robot); Correct 48.If a variable in a superclass is private, could it be directly accessed or modified by a subclass? Why or why not? Yes. A subclass inherits full access to all contents of its super class. Yes. Any variable passed through inheritance can be changed, but private methods cannot. No. A private variable can only be modified by the same class with which it is declared regardless of its inheritance. (*)


No. Nothing inherited by the super class can be changed in the subclass. Incorrect. Refer to Section 7 Lesson 4. 49.Which of the following show the correct UML representation of the super class Planet and its subclass Earth?


(*)

None of the above. Incorrect. Refer to Section 7 Lesson 4. 50.What is encapsulation?

A keyword that allows or restricts access to data and methods. 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 programming philosophy that promotes protecting data and hiding implementation in order to preserve the integrity of data and methods. (*) Incorrect. Refer to Section 7 Lesson 4.

Java Midterm exam

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