This project provides practical examples of core Java principles with simple, real-world implementations.

• Polymorphism (Intermediate)
  Example: PaymentProcessingExample.java – demonstrates interfaces and multiple implementations.

• Encapsulation (Beginner)
  Example: BankAccount class – protects its fields and enforces controlled access.

• Inheritance & Abstraction (Intermediate)
  Example: Vehicle hierarchy – shows how subclasses inherit behavior and implement abstract methods.

• Collections Framework (Intermediate)
  Examples: Use of List, Set, and Map to manage groups of objects efficiently.

• Exception Handling (Beginner)
  Example: Demonstrates try-catch-finally blocks for robust error handling.

• Linked List (Intermediate)
  Example: LinkedListExample.java – custom implementation of a singly linked list.

• Stack (Beginner)
  Example: StackExample.java – push, pop, and peek operations using both arrays and Deque.

• Queue (Beginner)
  Example: QueueExample.java – FIFO operations implemented with LinkedList.

• Binary Search Tree (BST) (Advanced)
  Example: BinarySearchTreeExample.java – insert, search, and in-order traversal of nodes.

• HashMap Usage (Intermediate)
  Example: HashMapExample.java – demonstrates storing and retrieving key-value pairs efficiently.

Each example can be compiled and executed from the root directory of the project using the command line.

Example: Run the Polymorphism demo

# Compile the Java file into .class bytecode
javac com/java_journey/concepts/PaymentProcessingExample.java  

# Run using the fully qualified class name
java com.java_journey.concepts.PaymentProcessingExample