All Flashcards
What is an ArrayList?
A dynamic data structure that stores an ordered collection of items.
What does 'mutable' mean in the context of ArrayLists?
Elements can be changed after the ArrayList is created.
What is a wrapper class?
A class that encapsulates a primitive data type, turning it into an object.
What is linear search?
A method for finding a target element in a list by checking each element sequentially.
Define selection sort.
A sorting algorithm that repeatedly finds the minimum element and moves it to the sorted portion of the list.
Define insertion sort.
A sorting algorithm that inserts each element into its correct position in the already sorted portion of the list.
What is encryption?
The process of converting plain text into a code to protect data from unauthorized access.
What is traversing an ArrayList?
Accessing and processing each element in the ArrayList, usually within a loop.
What is the Java Collections Framework?
A set of interfaces and classes that provide implementations for common data structures.
Define personal data.
Any information that relates to an identifiable individual.
Why are ArrayLists more versatile than arrays?
ArrayLists are dynamic in size, allowing addition and removal of elements.
What is the purpose of the size() method in ArrayLists?
Returns the number of elements currently in the ArrayList.
Why must ArrayLists store objects instead of primitive types?
ArrayLists are designed to hold objects; primitive types must be wrapped in their corresponding class.
What is the significance of the import java.util.ArrayList; statement?
It makes the ArrayList class available for use in your Java code.
Explain the concept of traversing an ArrayList.
Iterating through each element of the ArrayList to perform an operation.
What is the purpose of searching in an ArrayList?
To find a specific element within the ArrayList.
What is the purpose of sorting an ArrayList?
To arrange the elements of the ArrayList in a specific order.
What is the ethical consideration when collecting user data?
Protecting user privacy and using data responsibly.
What does it mean for an ArrayList to be 'dynamic'?
Its size can change during runtime; elements can be added or removed.
Why is transparency important regarding data collection?
Builds trust with users and allows them to make informed decisions.
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
list.add("apple");
list.add("banana");
System.out.println(list.size());
2
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(10);
list.add(20);
list.set(0, 15);
System.out.println(list.get(0));
15
Identify the error in the following code:
java
ArrayList<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
System.out.println(list.get(2));
IndexOutOfBoundsException: The index 2 is out of bounds for the list of size 2.
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
list.add("A");
list.add("B");
list.remove(0);
System.out.println(list.size());
1
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(5);
list.add(10);
list.add(5);
int index = list.indexOf(5);
System.out.println(index);
0
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
System.out.println(list.size());
0
Identify the error in the following code:
java
ArrayList<int> list = new ArrayList<>();
ArrayLists cannot store primitive types directly. Use the Integer wrapper class instead: ArrayList
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
list.add(3);
list.clear();
System.out.println(list.size());
0
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
list.add("apple");
list.add("banana");
System.out.println(list.get(1));
banana
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(5);
list.add(10);
list.remove(Integer.valueOf(5));
System.out.println(list.size());
1