Module 18: Java Collections Framework

📚 Introduction

The Java Collections Framework (JCF) is a set of classes and interfaces that implement commonly reusable data structures such as lists, sets, and maps.

🧱 Core Interfaces

• List: Ordered collection (e.g., ArrayList, LinkedList)
• Set: Unordered collection with no duplicates (e.g., HashSet, LinkedHashSet)
• Map: Key-value pairs (e.g., HashMap, TreeMap)

📋 Example: Using ArrayList

                    import java.util.*;
                    
                    public class ListExample {
                      public static void main(String[] args) {
                        List names = new ArrayList<>();
                        names.add("Alice");
                        names.add("Bob");
                        names.add("Charlie");
                    
                        for (String name : names) {
                          System.out.println(name);
                        }
                      }
                    }
                    

🔐 Example: Using HashMap

                    import java.util.*;
                    
                    public class MapExample {
                      public static void main(String[] args) {
                        Map map = new HashMap<>();
                        map.put(1, "Java");
                        map.put(2, "Python");
                        map.put(3, "C++");
                    
                        for (Map.Entry entry : map.entrySet()) {
                          System.out.println(entry.getKey() + ": " + entry.getValue());
                        }
                      }
                    }