SPRING '25 FINAL

Question 1

What are method modifiers?

Answer 1

Modifiers define the visibility or accessibility of the method

Examples include public, private, and protected.

Question 2

What is the return type of a method that does not return a value?

Answer 2

void

Indicates that the method does not return any value.

Question 3

What is included in a method’s definition?

Answer 3

Return type, method name, parameter list in parentheses

The method definition outlines how the method operates.

Question 4

What happens when a method is called in terms of memory?

Answer 4

A new memory space is created for the method

This allows for the method to execute without affecting the caller’s memory.

Question 5

In the context of memory, what does ‘max gets a new value X’ imply?

Answer 5

The variable max receives a new value during method execution

This indicates the method’s ability to change local variables.

Question 6

What is the purpose of the return statement in a method?

Answer 6

To return a value if there is a return type

If the method is void, no value will be returned.

Question 7

What is meant by ‘PassByReference’?

Answer 7

Refers to passing a reference to the original data, not a copy

Modifications to the data affect the original data.

Question 8

What is the difference between shallow copy and deep copy?

Answer 8

Shallow copy creates a new reference to the same object, deep copy creates a new object with its own data

Shallow copy shares the same elements, deep copy duplicates them.

Question 9

What does the operation ‘newArray = originalArray’ signify?

Answer 9

newArray references the same array object as originalArray

This is an example of shallow copying.

Question 10

Does modifying originalArray affect newArray?

Answer 10

Yes, if newArray is a shallow copy of originalArray

Changes to the original array will reflect in the new array.

Question 11

Fill in the blank: A block of code that performs a specific task is called a _______.

Answer 11

method

Methods are fundamental building blocks in programming.

Question 12

What does ‘workspace for main method’ refer to?

Answer 12

The memory space allocated for executing the main method

Each method has its own workspace to manage variables.

Question 13

True or False: The originalArray has random numbers filled by default.

Answer 13

False

By default, an array is filled with default values (e.g., 0 for integers).

Question 14

What is the significance of the ‘temp’ variable in swapping?

Answer 14

It temporarily holds a value to facilitate the swap

This is a common technique in variable swapping.

Question 15

What do you call the method that executes code to find the maximum value?

Answer 15

findMax

This method is likely designed to compare two values and return the larger one.

Question 16

What is the initial state of numA and numB in memory?

Answer 16

numA = 10, numB = 15

These are example values that would be used in operations.

Question 17

What does ‘workspace for findMax method’ indicate?

Answer 17

Memory space allocated for the execution of the findMax method

Each method’s execution is isolated in its own workspace.

Question 18

What is an array?

Answer 18

A container object that holds a fixed number of values of a single type

Each item in an array is called an element and is accessed by its numerical index.

Question 19

What is the default value for elements in a primitive type array?

Answer 19

0

For reference types, the default value is null.

Question 20

What is the syntax to declare an array of integers with a size of 5?

Answer 20

int[] scores = new int[5];

Question 21

What is a 2D array?

Answer 21

An array that holds data points in a matrix format

It can be visualized as having rows and columns.

Question 22

How do you access an element in a 2D array located at row 0, column 1?

Answer 22

data[0][1]

Question 23

What is the declaration syntax for a 2D array with 5 rows and 6 columns?

Answer 23

int[][] data = new int[5][6];

Question 24

What does data.length represent in a 2D array?

Answer 24

The size of the 1st dimension, which is the number of rows.

Question 25

What does data[i].length represent in a 2D array?

Answer 25

The size of the 2nd dimension, which is the number of columns.

Question 26

What is a jagged array?

Answer 26

An array of arrays where each sub-array can have different lengths ## Footnote This allows for a more flexible structure compared to a traditional rectangular array.

Question 27

What are parallel arrays?

Answer 27

A solution for problems with table-like data using several 1D arrays, one for each column.

Question 28

How do parallel arrays keep track of observations?

Answer 28

By using an index for each array to represent rows.

Question 29

Fill in the blank: A 2D array can be thought of as a _______.

Answer 29

matrix

Question 30

True or False: A parallel array is a language concept.

Answer 30

False ## Footnote It is a solution for managing data rather than a specific type in a programming language.

Question 31

What is the purpose of using parallel arrays in programming?

Answer 31

To calculate stats such as average score or max score from table-like data.

Question 32

What is the significance of the players.csv file in the context of parallel arrays?

Answer 32

It contains data lines after a header line, which can be used to populate parallel arrays.

Question 33

What is an ArrayList?

Answer 33

A resizable array of objects

Question 34

What type of elements can an ArrayList hold?

Answer 34

Any type of object, as long as the type is specified at declaration

Question 35

True or False: An ArrayList itself is an object.

Answer 35

True

Question 36

What happens to the size of an ArrayList when items are added or removed?

Answer 36

Automatically expands when a new item is added and shrinks when items are removed

Question 37

What interface does ArrayList implement?

Answer 37

List interface

Question 38

What is the syntax to declare an ArrayList for String objects?

Answer 38

ArrayList nameList = new ArrayList<>();

Question 39

What must be included when using ArrayList in Java?

Answer 39

import java.util.ArrayList;

Question 40

Fill in the blank: The type of the object to hold by the ArrayList is placed inside _______.

Answer 40

angled brackets <>

Question 41

What will happen if you try to put an object of a different type into an ArrayList?

Answer 41

An error will occur

Question 42

How do you print the contents of an ArrayList?

Answer 42

Using System.out.println(nameList) or System.out.println(nameList.toString())

Question 43

How can you determine what methods can be used with an ArrayList?

Answer 43

Consult the Java API documentation for ArrayList

Question 44

What are wrapper classes for primitive data types?

Answer 44

Classes that allow primitive types to be treated as objects

Question 45

List the primitive data types in Java.

Answer 45

* int * char * float * double

Question 46

List the corresponding wrapper classes for the primitive types.

Answer 46

* Integer * Character * Float * Double

Question 47

What is autoboxing?

Answer 47

Automatic conversion between primitive types and their corresponding object wrapper classes

Question 48

What is unboxing?

Answer 48

Converting an object of a wrapper type to its corresponding primitive value

Question 49

What is an object in Java?

Answer 49

An instance of a class that holds data fields and methods.

Question 50

What attributes does a 'Person' object typically have?

Answer 50

* ssn * name * age * gender * address

Question 51

What keyword is used to create an instance of an object in Java?

Answer 51

new

Question 52

What is a constructor in Java?

Answer 52

A method automatically called when an object is created, having the same name as the class with no return type.

Question 53

What does the default constructor do?

Answer 53

Sets all numerical fields to 0, boolean fields to false, and reference variables to null.

Question 54

What is the purpose of an instance field?

Answer 54

To store data specific to an object instance.

Question 55

What are instance methods?

Answer 55

Methods that operate on an instance of a class and are not declared with static.

Question 56

What is the difference between a setter and a getter?

Answer 56

* Setter: Stores or changes value in a field * Getter: Returns value from a field

Question 57

Why can't you directly access a private field outside its class?

Answer 57

Private fields are only visible to their own class.

Question 58

What is data hiding in Java?

Answer 58

Making class fields private to protect the object's privacy.

Question 59

What is the purpose of public methods in a class?

Answer 59

To provide access to private fields.

Question 60

What is the main advantage of encapsulation?

Answer 60

It protects an object's data and maintains integrity.

Question 61

What does UML stand for?

Answer 61

Unified Modeling Language

Question 62

What symbols are used in UML for access specifiers?

Answer 62

* + for public * - for private

Question 63

What is the typical order of elements in a class layout?

Answer 63

* Fields * Constructors * Setters and getters * Other methods

Question 64

Fill in the blank: A class can be considered a _______ data type.

Answer 64

custom

Question 65

What is the role of a no-arg constructor?

Answer 65

Overrides the default constructor to set sensitive defaults.

Question 66

How can you generate constructors, setters, and getters in Eclipse?

Answer 66

By using the Source menu to generate them after writing the data fields.

Question 67

True or False: Instance fields are shared among all instances of a class.

Answer 67

False

Question 68

What is the output of person1.getName()?

Answer 68

Returns the name of person1.

Question 69

What does the PrintWriter class do?

Answer 69

Used for writing formatted text to a file or output stream.

Question 70

What is the significance of a class being a blueprint?

Answer 70

It defines the structure and behavior of objects that can be instantiated.