Unit 7: ArrayLists

Question 1

add(E obj)

Answer 1

The add(E obj) method is used to insert an element into a collection such as an ArrayList or LinkedList.

Question 2

add(int index, E obj)

Answer 2

This method is used to insert an element at a specific index in an ArrayList. It shifts the existing elements to the right and increases the size of the ArrayList by one.

Question 3

Algorithms

Answer 3

Algorithms are step-by-step procedures or instructions for solving problems or performing tasks. They provide clear instructions on how to solve problems efficiently.

Question 4

ArrayList

Answer 4

A dynamic data structure that allows you to store and manipulate collections of objects. Unlike arrays, ArrayLists can grow or shrink dynamically as needed.

Question 5

ArrayList Algorithms

Answer 5

Refer to the various methods and operations that can be performed on an ArrayList, which is a dynamic array-like data structure in Java. These algorithms allow for efficient manipulation, retrieval, and modification of elements stored in an ArrayList.

Question 6

ArrayList constructor

Answer 6

A special method that creates an instance of the ArrayList class. It allows you to initialize an ArrayList object with specific elements or specify its initial capacity.

Question 7

ArrayList Methods

Answer 7

Built-in functions that allow us to manipulate and work with ArrayLists, which are dynamic arrays that can grow or shrink in size.

Question 8

Arrays

Answer 8

A collection of elements of the same data type, stored in contiguous memory locations. They have a fixed size and can be accessed using an index.

Question 9

Authentication and Access Controls

Answer 9

Refer to the processes and mechanisms used to verify the identity of users and regulate their access to computer systems or resources.

Question 10

ConcurrentModificationException

Answer 10

An exception occurs when a collection is modified while being iterated over using an iterator or enhanced for loop.

Question 11

Data Structure

Answer 11

A way of organizing and storing data in a computer so that it can be accessed and used efficiently. It provides a systematic way to manage and manipulate data.

Question 12

Delete element from ArrayList

Answer 12

Refers to the process of removing a specific item from the list, causing the remaining elements to shift down and fill the empty space.

Question 13

Encryption

Answer 13

The process of converting plain text into a secret code to protect sensitive information from unauthorized access.

Question 14

Enhanced For Loop (For-each Loop)

Answer 14

A simplified loop structure introduced in Java that allows easy iteration over arrays or collections without explicitly managing an index or iterator.

Question 15

Firewalls

Answer 15

Security systems that monitor and control incoming and outgoing network traffic based on predetermined security rules, protecting networks from unauthorized access or malicious activities.

Question 16

Import Statement

Answer 16

In Java is used to bring classes or packages from other libraries into your current program. It allows you to use those classes or packages without having to fully qualify their names.

Question 17

Initial capacity

Answer 17

Refers to the starting size or capacity allocated for an ArrayList when it is created using its constructor. It determines how many elements can be stored in the list before it needs to dynamically resize itself.

Question 18

Insert element in ArrayList

Answer 18

Refers to adding a new element at a specific position within the ArrayList. This operation shifts existing elements to accommodate the new element and maintains the order of the remaining elements.

Question 19

Insertion Sort

Answer 19

A simple sorting algorithm where each iteration removes one element from an input data set and inserts it into its correct position within a partially sorted list until all elements are inserted.

Question 20

Intrusion Detection Systems

Answer 20

Security tools designed to detect unauthorized access attempts or suspicious activities within computer networks or systems.

Question 21

Java Collections Framework

Answer 21

A set of classes and interfaces in Java that provide implementations of common data structures like lists, sets, and maps. It offers a unified interface for working with collections of objects.

Question 22

Linear Search

Answer 22

A simple searching algorithm that sequentially checks each element in a list until it finds the target value or reaches the end of the list.

Question 23

Selection Sort

Answer 23

A simple sorting algorithm that repeatedly finds the minimum element from an unsorted portion of the list and swaps it with the first element of that portion until the entire list is sorted.

Question 24

size()

Answer 24

A method that is used to determine the total number of elements present in a collection, such as a list or array.

Question 25

Traversing ArrayLists

Answer 25

Refers to the process of accessing and examining each element in an ArrayList. It involves iterating through the elements sequentially, usually using a loop.

Question 26

Wrapper Classes

Answer 26

Classes in Java that provide a way to wrap primitive data types into objects. They allow us to perform operations on primitives as if they were objects.

Question 27

ArrayLists

Answer 27

Dynamic arrays that can grow and shrink dynamically as needed. They provide resizable arrays with additional methods for easy manipulation and management.

Question 28

Autoboxing

Answer 28

The automatic conversion of a primitive data type to its corresponding wrapper class object. For example, when an int is assigned to an Integer object, autoboxing occurs.

Question 29

Constructor

Answer 29

A special method within a class that is used to initialize objects of that class. It is called automatically when an object is created and helps set initial values for its attributes.

Question 30

Deques

Answer 30

Short for double-ended queues, are data structures that allow insertion and removal of elements from both ends. They can be used to implement stacks and queues efficiently.

Question 31

Generics

Answer 31

In Java allow you to create classes and methods that can work with different types (e.g., integers, strings) without sacrificing type safety. They provide flexibility and reusability in your code.

Question 32

LinkedLists

Answer 32

Linear data structures where each element, called a node, contains a reference to the next node in the sequence. They provide efficient insertion and deletion operations but have slower access times compared to arrays.

Question 33

Maps

Answer 33

Also known as dictionaries or associative arrays, are data structures that store key-value pairs. They allow efficient retrieval of values based on their corresponding keys.

Question 34

Type Checking

Answer 34

Refers to the process of verifying whether the usage of types in a program is consistent with their definitions. It helps catch errors at compile-time by ensuring that operations are performed on compatible types.

Question 35

Unboxing

Answer 35

The automatic conversion of a wrapper class object to its corresponding primitive data type. For example, when an Integer object is assigned to an int variable, unboxing occurs.

Question 36

get(int index)

Answer 36

A method that is used to retrieve the element at a specific index in an array or list.

Question 37

remove(int index)

Answer 37

A method that is used to delete an element from a list at a specific index position.

Question 38

set(int index, E obj)

Answer 38

A method that is used to replace an element in a list at a specific index position with a new element.

Question 39

add()

Answer 39

A method that is used to insert an element into a data structure, such as a list or set.

Question 40

Enhanced For Loop

Answer 40

Also known as a foreach loop) is a simplified way to iterate over elements in an array or collection. It automatically handles indexing and provides an easy way to access each element without explicitly using indices.

Question 41

For Loop

Answer 41

A control flow statement that allows you to repeatedly execute a block of code for a specified number of times or until certain conditions are met.

Question 42

get()

Answer 42

A method that is used to retrieve the value of an element at a specific index in a list or array.

Question 43

IndexOutOfBoundsException

Answer 43

An exception that occurs when trying to access an invalid index position within an array or collection.

Question 44

remove()

Answer 44

A method removes an element from a collection, if it exists, and returns true. If the element doesn’t exist, it returns false.

Question 45

set()

Answer 45

Acollection of unique elements with no specific order. It does not allow duplicate values.

Question 46

size()

Answer 46

A method is used to determine the total number of elements present in a collection, such as a list or array.

Question 47

% operator (modulus)

Answer 47

Also known as the modulus operator, returns the remainder of a division operation. It is used to find the remainder when one number is divided by another.

Question 48

+= operator

Answer 48

An operator is known as an assignment operator. It adds the value on the right-hand side of the operator to the variable on the left-hand side and assigns the result back to that variable.

Question 49

boolean

Answer 49

A data type that can only have two possible values - true or false. It is often used in programming to make decisions and control the flow of a program.

Question 50

get

Answer 50

This term refers to retrieving the value of a variable or an object’s property.

Question 51

if statement

Answer 51

A programming construct that allows the execution of a block of code only if a certain condition is true.

Question 52

Private

Answer 52

In the context of programming, refers to a visibility modifier that restricts access to certain variables or methods within a class. It means that only other members of the same class can access those private elements.

Question 53

return

Answer 53

A keyword is used in functions/methods to send back a value to the caller. It terminates the execution of a function and passes control back to where it was called from.

Question 54

Binary Search

Answer 54

An efficient algorithm used to locate a target value within a sorted array by repeatedly dividing the search interval in half.

Question 55

Linear/Sequential Search

Answer 55

A simple searching algorithm that checks each element in a list one by one until it finds a match or reaches the end of the list. It is commonly used when there is no specific order or structure to the data.

Question 56

Ascending Order

Answer 56

Refers to arranging items in increasing numerical or alphabetical value. The smallest value comes first, followed by larger values.

Question 57

Descending Order

Answer 57

Refers to arranging items or numbers from highest to lowest value.

Question 58

Merge Sort

Answer 58

An efficient, comparison-based sorting algorithm that divides an unsorted list into smaller sublists, sorts those sublists recursively, and then merges them back together to obtain a sorted list.

Question 59

Pseudocode

Answer 59

A simplified programming language that uses plain English to outline the logic of a program. It helps programmers plan and communicate their ideas before writing actual code.

Question 60

Runtime Comparisons

Answer 60

Refer to the analysis and evaluation of the efficiency and speed of different algorithms or programs during execution.

Question 61

Sorting

Answer 61

Refers to arranging a collection of items in a specific order, such as ascending or descending order, based on certain criteria.

Question 62

Swap

Answer 62

Refers to exchanging the values of two variables or elements in an array. It allows you to rearrange data without losing any information.

Question 63

Traverse

Answer 63

Refers to the process of accessing each element in a data structure (such as arrays or linked lists) one by one, usually for performing some operation on them.

Question 64

Ciphers

Answer 64

Algorithms used for encryption and decryption of messages or data. They transform plaintext (original message) into ciphertext (encrypted message) using specific rules or keys, making it difficult for unauthorized individuals to understand or access sensitive information.

Question 65

Cryptography

Answer 65

Refers to techniques used for secure communication in the presence of adversaries. It involves encoding information in such a way that only authorized parties can understand it.

Question 66

Encapsulation

Answer 66

Refers to the bundling of data and methods within a class, where the data is hidden from external access. It ensures that an object’s internal state remains consistent by controlling how it can be accessed or modified.

Question 67

Hash Functions

Answer 67

Mathematical algorithms that take an input (or message) and produce a fixed-size string of characters, which is typically a hash value or hash code. The output is unique to the input, meaning even a small change in the input will result in a significantly different hash value.