import java.util.
ArrayList;
public class ArrayListExample {
public static void main(String[] args) {
// Creating an ArrayList of Strings
ArrayList<String> fruits = new ArrayList<>();
// Adding elements to the ArrayList
fruits.add("Apple");
fruits.add("Banana");
fruits.add("Mango");
fruits.add("Orange");
// Displaying the ArrayList
System.out.println("Fruits List: " + fruits);
// Accessing an element
System.out.println("First fruit: " + fruits.get(0));
// Removing an element
fruits.remove("Banana");
System.out.println("After removing Banana: " + fruits);
// Updating an element
fruits.set(1, "Grapes");
System.out.println("After updating: " + fruits);
// Looping through elements
System.out.println("All fruits:");
for (String fruit : fruits) {
System.out.println(fruit);
}
}
}
OUTPUT
Fruits List: [Apple, Banana, Mango, Orange]
First fruit: Apple
After removing Banana: [Apple, Mango, Orange]
After updating: [Apple, Grapes, Orange]
All fruits:
Apple
Grapes
Orange
import java.util.LinkedList;
public class LinkedListExample {
public static void main(String[] args) {
// Creating a LinkedList of Strings
LinkedList<String> animals = new LinkedList<>();
// Adding elements to the LinkedList
animals.add("Dog");
animals.add("Cat");
animals.add("Cow");
animals.add("Horse");
// Displaying the LinkedList
System.out.println("Animals List: " + animals);
// Adding element at the beginning and end
animals.addFirst("Elephant");
animals.addLast("Goat");
System.out.println("After adding first and last: " + animals);
// Removing an element
animals.remove("Cat");
System.out.println("After removing Cat: " + animals);
// Accessing an element
System.out.println("First animal: " + animals.getFirst());
// Looping through elements
System.out.println("All animals:");
for (String animal : animals) {
System.out.println(animal);
}
}
}
OUTPUT
Animals List: [Dog, Cat, Cow, Horse]
After adding first and last: [Elephant, Dog, Cat, Cow, Horse, Goat]
After removing Cat: [Elephant, Dog, Cow, Horse, Goat]
First animal: Elephant
All animals:
Elephant
Dog
Cow
Horse
Goat
import java.util.Stack;
public class StackExample {
public static void main(String[] args) {
// Creating a Stack of Strings
Stack<String> books = new Stack<>();
// Pushing elements onto the Stack
books.push("Math");
books.push("Science");
books.push("History");
// Displaying the Stack
System.out.println("Stack: " + books);
// Peeking the top element
System.out.println("Top element: " + books.peek());
// Popping an element
books.pop();
System.out.println("After pop: " + books);
// Checking if stack is empty
System.out.println("Is stack empty? " + books.isEmpty());
// Iterating through the Stack
System.out.println("All elements:");
for (String book : books) {
System.out.println(book);
}
}
}
OUTPUT
Stack: [Math, Science, History]
Top element: History
After pop: [Math, Science]
Is stack empty? false
All elements:
Math
Science
import java.util.Queue;
import java.util.LinkedList;
public class QueueExample {
public static void main(String[] args) {
// Creating a Queue of Strings
Queue<String> tasks = new LinkedList<>();
// Adding elements to the Queue (Enqueue)
tasks.add("Task1");
tasks.add("Task2");
tasks.add("Task3");
// Displaying the Queue
System.out.println("Queue: " + tasks);
// Accessing the front element without removing (Peek)
System.out.println("Front of queue: " + tasks.peek());
// Removing elements from the Queue (Dequeue)
tasks.poll(); // removes "Task1"
System.out.println("After poll: " + tasks);
// Checking if queue is empty
System.out.println("Is queue empty? " + tasks.isEmpty());
// Iterating through the Queue
System.out.println("Remaining tasks:");
for (String task : tasks) {
System.out.println(task);
} OUTPUT
Queue: [Task1, Task2, Task3]
Front of queue: Task1
After poll: [Task2, Task3]
is queue empty? false
Remaining tasks:
Task2
Task3
}
}
import java.util.HashSet;
public class HashSetExample {
public static void main(String[] args) {
// Creating a HashSet of Strings
HashSet<String> cities = new HashSet<>();
// Adding elements to the HashSet
cities.add("Delhi");
cities.add("Mumbai");
cities.add("Chennai");
cities.add("Kolkata");
// Trying to add a duplicate element
cities.add("Mumbai"); // Will not be added
// Displaying the HashSet
System.out.println("Cities Set: " + cities);
// Checking if an element exists
System.out.println("Contains Delhi? " + cities.contains("Delhi"));
// Removing an element
cities.remove("Chennai");
System.out.println("After removing Chennai: " + cities);
// Iterating through the HashSet
System.out.println("All cities:");
for (String city : cities) {
System.out.println(city);
}
}
}
OUTPUT
Cities Set: [Kolkata, Mumbai, Delhi, Chennai]
Contains Delhi? true
Ater removing Chennai: [Kolkata, Mumbai, Delhi]
All cities:
Kolkata
Mumbai
Delhi
import java.util.LinkedHashSet;
public class LinkedHashSetExample {
public static void main(String[] args) {
// Creating a LinkedHashSet of Strings
LinkedHashSet<String> languages = new LinkedHashSet<>();
// Adding elements to the LinkedHashSet
languages.add("Java");
languages.add("Python");
languages.add("C++");
languages.add("JavaScript");
// Trying to add a duplicate element
languages.add("Python"); // Will not be added
// Displaying the LinkedHashSet
System.out.println("Programming Languages: " + languages);
// Checking for an element
System.out.println("Contains Java? " + languages.contains("Java"));
// Removing an element
languages.remove("C++");
System.out.println("After removing C++: " + languages);
// Iterating through the LinkedHashSet
System.out.println("All languages:");
for (String lang : languages) {
System.out.println(lang);
}
}
}
OUTPUT
Programming Languages: [Java, Python, C++, JavaScript]
Contains Java? true
After removing C++: [Java, Python, JavaScript]
All languages:
Java
Python
JavaScript
import java.util.SortedSet;
import java.util.TreeSet;
public class TreeSetExample {
public static void main(String[] args) {
// Creating a SortedSet using TreeSet
SortedSet<String> countries = new TreeSet<>();
// Adding elements (automatically sorted)
countries.add("India");
countries.add("Australia");
countries.add("USA");
countries.add("Germany");
// Attempt to add duplicate
countries.add("India"); // Duplicate, will not be added OUTPUT
Countries: [Australia,
// Displaying the TreeSet (sorted order) Germany, India, USA]
System.out.println("Countries: " + countries); First Country: Australia
Last Country: USA
// Getting first and last elements
After removing Germany:
System.out.println("First Country: " + countries.first());
[Australia, India, USA]
System.out.println("Last Country: " + countries.last());
All countries:
// Removing an element Australia
countries.remove("Germany"); India
System.out.println("After removing Germany: " + countries); USA
// Iterating through the TreeSet
System.out.println("All countries:");
for (String country : countries) {
System.out.println(country);
}
}
}
import java.util.Map;
import java.util.HashMap;
public class HashMapExample {
public static void main(String[] args) {
// Creating a Map using HashMap
Map<Integer, String> studentMap = new HashMap<>();
// Adding key-value pairs to the map
studentMap.put(101, "Alice");
studentMap.put(102, "Bob");
studentMap.put(103, "Charlie");
// Displaying the map
System.out.println("Student Map: " + studentMap);
// Accessing a value by key
System.out.println("Student with ID 102: " + studentMap.get(102));
// Removing an entry by key
studentMap.remove(101);
System.out.println("After removing ID 101: " + studentMap);
// Checking if a key exists
System.out.println("Contains key 103? " + studentMap.containsKey(103));
// Iterating through the map
System.out.println("All students:");
for (Map.Entry<Integer, String> entry : studentMap.entrySet()) {
System.out.println("ID: " + entry.getKey() + ", Name: " + entry.getValue());
}
}
}
OUTPUT
Student Map: {101=Alice, 102=Bob, 103=Charlie}
Student with ID 102: Bob
After removing ID 101: {102=Bob, 103=Charlie}
Contains key 103? true
All students:
ID: 102, Name: Bob
ID: 103, Name: Charlie
