JAVA-OOP-Finals-Mock

Tags: #◇CCPROG3 #◇Object-Oriented Concepts #◇Programming #◇Computer Science #◇Java #◇Object-Oriented Programming #◇Software Engineering Principles #◇Algorithms

◇Overview

Instructions:

◇Details / Theory

JAVA OOP Master Class: Final Mock Exam

Instructions:
Time Limit: 2 Hours (Recommended) Total Items: 70 Formats:

1. Multiple Choice (Theory) - 30 Items
2. UML Analysis (Diagrams) - 15 Items
3. Code Analysis (Tracing) - 25 Items

◇Part I: Multiple Choice (Theory & Concepts)

Select the best answer for each question.

1. Which programming paradigm focuses on "entities" (nouns) rather than "actions" (verbs)?
   A) Procedural Programming
   B) Functional Programming
   C) Object-Oriented Programming
   D) Scripting

2. Where are Primitive Data Types stored in Java memory?
   A) Heap
   B) Stack
   C) Class Area
   D) String Pool

3. What is the default value of a Reference Type (e.g., String, Student) if not initialized?
   A) 0
   B) false
   C) null
   D) undefined

4. Which keyword is used to create a constant variable that cannot be changed once assigned?
   A) static
   B) const
   C) final
   D) abstract

5. If a method is declared static, which of the following is TRUE?
   A) It can access non-static instance variables directly.
   B) It belongs to the object instance.
   C) It can be called without creating an object of the class.
   D) It cannot be called from the main method.

6. Which pillar of OOP involves hiding internal details and providing a public interface?
   A) Inheritance
   B) Polymorphism
   C) Encapsulation
   D) Abstraction

7. In Encapsulation, what is the standard visibility for class attributes (fields)?
   A) public
   B) private
   C) protected
   D) default

8. What is the return type of a Constructor?
   A) void
   B) The class name
   C) int
   D) It has no return type

9. Which relationship is described as "Has-a" where the part can exist independently of the whole?
   A) Association
   B) Composition
   C) Aggregation
   D) Inheritance

10. Which relationship implies a strong lifecycle dependency (if the container dies, the part dies)?
    A) Association
    B) Composition
    C) Aggregation
    D) Dependency

11. Which Collection interface does NOT allow duplicate elements?
    A) List
    B) ArrayList
    C) Set
    D) LinkedList

12. Which List implementation is best for frequent insertion and deletion of elements?
    A) ArrayList
    B) LinkedList
    C) Vector
    D) Array

13. What is the process of automatically converting a primitive int to an Integer object?
    A) Casting
    B) Unboxing
    C) Autoboxing
    D) Wrapping

14. Which keyword is used to inherit from a class?
    A) implements
    B) inherits
    C) extends
    D) super

15. In Java, how many classes can a single class extend (inherit from)?
    A) One
    B) Two
    C) Unlimited
    D) Zero

16. What does super() do in a constructor?
    A) Calls the superclass's method.
    B) Calls the superclass's constructor.
    C) Creates a new instance of the parent.
    D) Accesses a private variable in the parent.

17. Which type of Polymorphism is achieved via Method Overloading?
    A) Runtime Polymorphism
    B) Dynamic Binding
    C) Compile-time Polymorphism
    D) Ad-hoc Polymorphism

18. Which method is used to compare the content of two String objects?
    A) ==
    B) compare()
    C) equals()
    D) =

19. What happens if you try to instantiate an Abstract Class?
    A) It creates a null object.
    B) It throws a RuntimeException.
    C) It causes a Compilation Error.
    D) It works normally.

20. Which of the following is TRUE about Interfaces?
    A) They can have constructors.
    B) Methods are implicitly private.
    C) A class can implement multiple interfaces.
    D) Variables are mutable (can be changed).

21. Which keyword is used to implement an Interface?
    A) extends
    B) implements
    C) interface
    D) using

22. In the Exception Hierarchy, which class is the root of all errors and exceptions?
    A) Exception
    B) RuntimeException
    C) Throwable
    D) Error

23. Which block in exception handling executes regardless of whether an exception occurred or not?
    A) try
    B) catch
    C) finally
    D) throws

24. Which type of exception is checked at compile-time?
    A) NullPointerException
    B) ArithmeticException
    C) IOException
    D) ArrayIndexOutOfBoundsException

25. What is the correct way to declare that a method might throw an exception?
    A) void method() catch Exception
    B) void method() throw Exception
    C) void method() throws Exception
    D) void method() try Exception

26. In MVC, which component handles user input and updates the Model?
    A) Model
    B) View
    C) Controller
    D) Database

27. Which Swing component represents a clickable button?
    A) JLabel
    B) JTextField
    C) JButton
    D) JPanel

28. What is the purpose of Math.random()?
    A) Returns a random int between 0 and 100.
    B) Returns a random double between 0.0 and 1.0.
    C) Returns a random boolean.
    D) Returns a random char.

29. Which access modifier allows access ONLY within the same class?
    A) public
    B) protected
    C) default
    D) private

30. What is "Dynamic Binding"?
    A) Linking a method call to the method body at compile-time.
    B) Linking a method call to the method body at runtime based on the object type.
    C) Binding a variable to a value.
    D) Importing a library dynamically.

◇Part II: UML Analysis (Diagram Logic)

Analyze the diagrams and answer the questions.

Diagram A:

+---------------------+
|      Account        |
+---------------------+
| - balance : double  |
+---------------------+
| + deposit(a: double)|
+---------------------+

31. What is the visibility of the balance attribute?
    A) Public
    B) Private
    C) Protected
    D) Package/Default

32. What is the visibility of the deposit method?
    A) Public
    B) Private
    C) Protected
    D) Package/Default

Diagram B:

[Team] <*>(consists of)---- [Player]

(Note: The diamond is filled/solid)

33. What relationship does this diagram represent?
    A) Association
    B) Aggregation
    C) Composition
    D) Inheritance

34. If the Team object is destroyed, what happens to the Player objects?
    A) They continue to exist.
    B) They are also destroyed.
    C) They are moved to another Team.
    D) Nothing happens.

Diagram C:

[Department] <>(has)---- [Teacher]

(Note: The diamond is empty/hollow)

35. What relationship does this diagram represent?
    A) Association
    B) Aggregation
    C) Composition
    D) Inheritance

36. If the Department is closed, what happens to the Teacher objects?
    A) They cease to exist.
    B) They continue to exist independently.
    C) They become null.
    D) They are garbage collected immediately.

Diagram D:

      [Vehicle]
         ^
         |
     (extends)
         |
       [Car]

(Note: Solid line with closed, empty arrow pointing to Vehicle)

37. Which class is the Superclass?
    A) Vehicle
    B) Car
    C) Both
    D) Neither

38. How would you write this in Java?
    A) class Vehicle extends Car
    B) class Car implements Vehicle
    C) class Car extends Vehicle
    D) class Vehicle implements Car

Diagram E:

   <<interface>>
    [Playable]
         ^
         |
    (implements)
         |
      [Guitar]

(Note: Dashed line with closed, empty arrow pointing to Playable)

39. What does the <<interface>> stereotype imply about Playable?
    A) It is a normal class.
    B) It cannot be instantiated and has abstract methods.
    C) It is a final class.
    D) It is a primitive type.

40. How would you write this in Java?
    A) class Guitar extends Playable
    B) class Guitar implements Playable
    C) interface Guitar extends Playable
    D) abstract Guitar implements Playable

Diagram F (Multiplicity):

[Order] "1" ---- "0..*" [Item]

41. How many Item objects can be associated with one Order?
    A) Exactly one.
    B) Zero or one.
    C) Zero to many.
    D) One to many.

42. How many Order objects is an Item associated with?
    A) Exactly one.
    B) Zero or one.
    C) Many.
    D) Unknown.

General UML Symbols:

43. What does the # symbol represent?
    A) Public
    B) Private
    C) Protected
    D) Static

44. What does an underlined method name (e.g., <u>getCount()</u>) represent?
    A) Abstract method
    B) Static method
    C) Final method
    D) Void method

45. What does an italicized class name (e.g., Shape) represent?
    A) Abstract class
    B) Interface
    C) Static class
    D) Final class

◇Part III: Code Analysis (Tracing & Output)

Analyze the code snippets and determine the output or result.

Snippet 1: Static vs Instance

class Counter {
    static int count = 0;
    int id = 0;
    Counter() { count++; id = count; }
}
// Main:
Counter c1 = new Counter();
Counter c2 = new Counter();
System.out.println(c1.id + " " + Counter.count);

46. What is the output?
    A) 1 1
    B) 1 2
    C) 2 2
    D) 2 1

Snippet 2: String Equality

String s1 = "Java";
String s2 = new String("Java");
System.out.println(s1 == s2);
System.out.println(s1.equals(s2));

47. What is the output?
    A) true true
    B) false false
    C) false true
    D) true false

Snippet 3: Polymorphism

class A { void show() { System.out.print("A"); } }
class B extends A { void show() { System.out.print("B"); } }
// Main:
A obj = new B();
obj.show();

48. What is the output?
    A) A
    B) B
    C) AB
    D) Compilation Error

Snippet 4: Inheritance & Constructors

class Parent {
    Parent() { System.out.print("P "); }
}
class Child extends Parent {
    Child() { System.out.print("C "); }
}
// Main:
new Child();

49. What is the output?
    A) C
    B) P
    C) C P
    D) P C

Snippet 5: Arrays

int[] arr = {1, 2, 3};
try {
    System.out.println(arr[3]);
} catch (Exception e) {
    System.out.print("Error");
} finally {
    System.out.print(" Done");
}

50. What is the output?
    A) 3 Done
    B) Error
    C) Error Done
    D) Done

Snippet 6: ArrayList

ArrayList<String> list = new ArrayList<>();
list.add("A");
list.add("B");
list.add(1, "C");
System.out.println(list);

51. What is the output?
    A) [A, B, C]
    B) [A, C, B]
    C) [C, A, B]
    D) [C, B, A]

Snippet 7: Abstract Classes

abstract class Shape { abstract void draw(); }
// Main:
Shape s = new Shape();
s.draw();

52. What is the result?
    A) Runs successfully, does nothing.
    B) Prints "null".
    C) Compilation Error (Cannot instantiate).
    D) Runtime Exception.

Snippet 8: Method Overloading

void print(int a) { System.out.print("Int"); }
void print(double a) { System.out.print("Double"); }
// Main:
print(10);
print(10.5);

53. What is the output?
    A) IntDouble
    B) DoubleInt
    C) IntInt
    D) DoubleDouble

Snippet 9: Exception Flow

try {
    throw new Exception();
} catch (Exception e) {
    System.out.print("Caught ");
}
System.out.print("Next");

54. What is the output?
    A) Caught
    B) Next
    C) Caught Next
    D) Runtime Error

Snippet 10: Interface Variables

interface Data { int X = 10; }
// Main:
// Data.X = 20; // Line 1
System.out.println(Data.X);

55. If Line 1 is uncommented, what happens?
    A) X becomes 20.
    B) Compilation Error (Cannot assign to final variable).
    C) Runtime Error.
    D) Nothing.

Snippet 11: Casting

double d = 9.99;
int i = (int) d;
System.out.println(i);

56. What is the output?
    A) 9.99
    B) 10
    C) 9
    D) Error

Snippet 12: Boolean Logic

boolean b1 = true;
boolean b2 = false;
System.out.println(b1 && b2);

57. What is the output?
    A) true
    B) false
    C) null
    D) 1

Snippet 13: String Immutability

String s = "Java";
s.concat(" Rules");
System.out.println(s);

58. What is the output?
    A) Java Rules
    B) Java
    C) Rules
    D) null

Snippet 14: Modulo Operator

System.out.println(10 % 3);

59. What is the output?
    A) 3
    B) 1
    C) 3.33
    D) 0

Snippet 15: Loop Logic

for(int i=0; i<3; i++) {
    System.out.print(i);
}

60. What is the output?
    A) 012
    B) 123
    C) 0123
    D) 12

Snippet 16: Switch Statement

int x = 1;
switch(x) {
    case 1: System.out.print("One ");
    case 2: System.out.print("Two"); break;
}

61. What is the output?
    A) One
    B) One Two
    C) Two
    D) Error

Snippet 17: Object Equality

class A {}
A a1 = new A();
A a2 = new A();
System.out.println(a1.equals(a2));

62. What is the output (assuming equals is NOT overridden)?
    A) true
    B) false
    C) null
    D) Error

Snippet 18: Integer Division

System.out.println(5 / 2);

63. What is the output?
    A) 2.5
    B) 2
    C) 3
    D) 2.0

Snippet 19: Post-Increment

int x = 5;
System.out.println(x++);
System.out.println(x);

64. What is the output?
    A) 5 6
    B) 6 6
    C) 5 5
    D) 6 5

Snippet 20: Array Index

int[] a = new int[5];
System.out.println(a[5]);

65. What is the result?
    A) 0
    B) null
    C) ArrayIndexOutOfBoundsException
    D) 5

Snippet 21: this keyword

class A {
    int x = 10;
    void set(int x) {
        this.x = x;
    }
}
// Main:
A a = new A();
a.set(20);
System.out.println(a.x);

66. What is the output?
    A) 10
    B) 20
    C) 0
    D) Error

Snippet 22: super keyword

class P { int x = 10; }
class C extends P {
    int x = 20;
    void print() { System.out.print(super.x); }
}
// Main:
new C().print();

67. What is the output?
    A) 10
    B) 20
    C) 30
    D) Error

Snippet 23: NullPointerException

String s = null;
try {
    System.out.println(s.length());
} catch(NullPointerException e) {
    System.out.print("Null");
}

68. What is the output?
    A) 0
    B) Null
    C) Runtime Error (Crash)
    D) null

Snippet 24: 2D Array

int[][] arr = { {1, 2}, {3, 4} };
System.out.println(arr[1][0]);

69. What is the output?
    A) 1
    B) 2
    C) 3
    D) 4

Snippet 25: Final Variable

final int x = 10;
// x = 20; // Uncommenting this line
System.out.println(x);

70. What happens if the line is uncommented?
    A) Prints 20
    B) Prints 10
    C) Compilation Error
    D) Runtime Error

End of Exam

◇Common Pitfalls

Rushing code-tracing questions without tracking the exact state of variables at each step. Confusing UML diamond types — filled diamond = composition (strong ownership), empty diamond = aggregation (weak ownership). Not accounting for finally blocks that always execute, even when exceptions are thrown or caught. Forgetting integer division truncation in Java: 7 / 2 = 3, not 3.5.

◇Summary

TL;DR — 70-item mock exam: 30 theory (OOP concepts), 15 UML analysis (visibility, relationships), and 25 code tracing (polymorphism, exceptions, collections, casting). Full coverage of CCPROG3 Java OOP syllabus.

◇Links

Related: Source / Reference:

Made by 2ru17

Please contact me through discord or my the university email for any problems regarding the reviewer. Thanks!

◇References & Navigation

• Related Notes: ◇Object-Oriented Programming in Java