🚨 I thought I understood Java Multithreading… until it broke my logic I started with a simple idea: 👉 Build a Bank Transaction System (deposit, withdraw, transfer) Easy, right? Then I added threads. And suddenly… Same account was getting updated by multiple threads Balances didn’t make sense Logs were completely messed up Even when code looked “correct”… output wasn’t That’s when I realized: 👉 Multithreading is not about writing threads 👉 It’s about controlling who touches data and when 💥 So I rebuilt it step by step: 1️⃣ Started simple Single-threaded system → everything worked perfectly 2️⃣ Introduced Executor Framework Used ExecutorService to run multiple transactions concurrently → Cleaner and more scalable than manual threads 3️⃣ Hit race conditions Multiple withdrawals on the same account broke consistency 4️⃣ Fixed with synchronized Made deposit & withdraw thread-safe → But transfer was still tricky 5️⃣ Enter ReentrantLock Used locks per account for transfer → Now managing two resources at once 6️⃣ Faced deadlock risk 😬 Two threads: A → B B → A Both got stuck. 7️⃣ Solved it with lock ordering Always lock smaller account ID first → Deadlock gone ✅ 😵 Then came another problem… Even when logic was correct → logs looked WRONG Example: Withdraw shows balance = 400 Deposit also shows 400 Nothing made sense 👉 Root cause: Logs were reading shared state after other threads modified it Final fix 🔥 I introduced a result object: 👉 each operation returns its own exact balance + status Now logs finally reflect reality: pool-1-thread-1 | TXN:101 | WITHDRAW | ACC:1001 | SUCCESS | Balance: 500 pool-1-thread-2 | TXN:108 | TRANSFER | FAILED | Insufficient balance 🧠 What I actually learned: Executor Framework > manual thread creation synchronized vs ReentrantLock (control matters) Race conditions are subtle but dangerous Deadlocks are real — and avoidable with design Logging in multithreaded systems is harder than it looks Concurrency is more about thinking correctly than coding This project changed my understanding from: 👉 “I can use threads” to 👉 “I can design thread-safe systems” If you’ve ever struggled with multithreading, I’d love to hear your experience 👇 #Java #Multithreading #ExecutorService #ReentrantLock #Concurrency #BackendDevelopment #LearningInPublic #SoftwareEngineering #JavaProjects

I’ve been working on strengthening my Java fundamentals, and I built a basic small banking system to put those concepts into practice.Not just watching tutorial. This is a console-based application, but the goal wasn’t just to “make it work”—I focused on writing cleaner and more structured code. What it currently supports:User login system,Deposit and withdrawal operations,Balance checking,Transaction history Simple menu-driven flow While building this, I spent time understanding how to properly use OOP concepts like encapsulation, abstraction, and interfaces. One change that really improved the code was moving all the logic out of the main method into a separate BankApp class. That made the program easier to read and extend. I also used an interface (Accountable) to define the core banking operations, which helped me think more in terms of design rather than just implementation. GitHub: https://lnkd.in/gyVTmny2 This is still a work in progress. Next, I’m planning to turn this into a proper backend application (possibly using Spring Boot) and add persistence. If you have suggestions or feedback, I’d genuinely appreciate it. #Java #BackendDevelopment #OOP #LearningInPublic

🚀 Java Series — Day 11: Encapsulation (Advanced Java Concept) Good developers write good code… Great developers protect their code 👀 Today, I explored Encapsulation in Java — a powerful concept used to secure data and control access in applications. 🔍 What I Learned: ✔️ Encapsulation = Wrapping data + controlling access ✔️ Use of private variables (data hiding) ✔️ Getters & Setters for controlled access ✔️ Improves security, flexibility & maintainability 💻 Code Insight: class BankAccount { private double balance; // hidden data public BankAccount(double initialBalance) { this.balance = initialBalance; } public double getBalance() { return balance; } } ⚡ Why Encapsulation is Important? 👉 Protects sensitive data 👉 Prevents unauthorized access 👉 Improves code flexibility 👉 Hides internal implementation 🌍 Real-World Examples: 💳 Banking systems (secure transactions) 📱 Mobile apps (user data protection) 🚗 Vehicles (controlled operations) 💡 Key Takeaway: Encapsulation helps you build secure, maintainable, and reliable applications by controlling access to data 🔐 📌 Next: Polymorphism & Runtime Behavior 🔥 #Java #OOPS #Encapsulation #JavaDeveloper #BackendDevelopment #CodingJourney #100DaysOfCode #LearnInPublic

"COBOL is the asbestos of programming languages." That's not my line — it's Wired's. $3 trillion in daily financial transactions. 43% of global banking systems. Average COBOL developer age: 55, with 10% retiring every year. This code is "dangerously difficult to remove." - https://lnkd.in/eeBg6eWg The article nails the problem. But most modernization approaches focus on translating code and hope the business logic comes  along for the ride. The real challenge is understanding what the code actually does before you touch it. Which behavior is a business rule that must be preserved? Which is a platform constraint from 1978 that should be eliminated?                     Sage-tech.AI's Cognitive Precompile analyzes 100% of the codebase — not a sample, not whatever fits in a context window — and separates business rules from platform artifacts. It traces constraints across files, flags artificial limitations for elimination, and catalogs every business rule with confidence scores and source references. Our modernization agentic workflow then queries that verified intelligence to produce a complete stakeholder review — target architecture, service decomposition, data schema mapping, UI transformation, business rule catalog — in hours instead of months. The same pipeline generates the modernized application: running microservices, database schema, and a modern UI replacing multiple green-screen terminals.                                           We've demonstrated this end-to-end with a real 48-year-old COBOL system — 1.3 million lines, 623 files. From analysis through running code to zero-downtime data migration with legacy and modern systems running side by side.               The Wired article asks the right question. We have built the answer.  See live demos at: https://lnkd.in/duTGHRr8                                                                   #LegacyModernization #COBOL #AIModernization #SageTechAI #MainframeModernization #AgenticAI

What I like about the Sage AI Technologies LLC approach to modernization is what Dave is talking about -- unlike other AI based modernization approaches, Sage Tech doesn't try to transcode or translate one language to another. In fact you don't even have to pick your modernization target before you start. Or you can choose multiple modernization targets and see which one works best. You access Sage Tech AI's cognitive model via its MCP server, providing the key context about the application that an LLM needs to generate accurate results.

I am excited to share a major milestone in my transition into Java Backend Development! 🚀 Before jumping straight into powerful frameworks, I wanted to deeply understand how enterprise architecture and build tools actually work under the hood. So, I built VaultBank—a fully functional, persistent Banking CLI application written in pure Java. Instead of writing a single script, I structured this project exactly how a real-world enterprise backend is designed. Here are the key technical concepts I implemented: 🔹 Maven Multi-Module Architecture: Designed a Parent POM to manage dependencies for separated core (business logic) and cli (user interface) modules. 🔹 Separation of Concerns: Isolated the strict banking rules and data state from the terminal interface using a dedicated Service Layer. 🔹 Data Serialization & File I/O: Integrated Google Gson to deserialize/serialize Java objects, ensuring account balances and transaction histories survive application restarts via a database.json file. 🔹 Automated Regression Testing: Wrote JUnit 5 tests in an isolated src/test environment to mathematically prove the banking logic is flawless before every build. 🔹 Fat JAR Packaging: Used the Maven Shade Plugin to bundle the application into a standalone, executable JAR file. Taking the time to build this without Spring Boot gave me a profound appreciation for what Maven actually does—from dependency management and the build lifecycle to keeping production code perfectly separated from testing logic. Now that the foundation is rock solid, the next stop is turning this architecture into a REST API with Spring Boot! ☕💻 #Java #BackendDevelopment #Maven #SoftwareEngineering #CareerTransition #JUnit #LearningInPublic

Project 1 - Console Based Banking application using Java Today I did something different. Instead of just learning concepts and moving on… I decided to apply everything in one place. While learning Java, I noticed a pattern: Write one example → understand → forget → move ahead. Same with DSA… We rarely use core Java concepts like OOP while solving problems. So before jumping into Spring Boot, I decided to build a console-based banking application. --- 💻 What I built: A simple system where you can: • Open an account • Deposit & withdraw money • Check balance • View account statements • List all accounts No database — just pure Java logic. --- 🧠 Key Learnings: 🔹 Interfaces as contracts → Defined clear rules for services and made code flexible 🔹 Using Map for data storage → Simulated database-like behavior in-memory 🔹 Project structure → Understood the purpose of Repository (data handling) and Service (business logic) 🔹 SOLID Principles → Wrote cleaner, maintainable, and scalable code 🔹 Lambda Expressions → Made code more concise and readable 🔹 Custom Exceptions → Handled edge cases like insufficient balance, account not found, etc. in a clean way 🔹 Hands-on experience → Biggest learning: concepts make more sense when you build something real --- 💡 Realization: You don’t truly understand Java by reading or solving small snippets… you understand it by building systems. This felt like the missing link between learning Java → and becoming ready for backend development. --- Next step → Taking this mindset into Spring Boot 🚀 --- Question 👇 Did building your first project change how you understood programming? #Java #OOP #BackendDevelopment #LearningInPublic #CodingJourney #Projects #SOLID

🚀 Java Project: Bank Application Development 💻 Day16 Today, I worked on building a Bank Application using Java, focusing on applying real-world concepts through Object-Oriented Programming (OOP). 🔹 Project Highlights: @Raviteja T I designed two main components: 📌 BankApplication (BLC) – Handles customer data & transactions 📌 Execution Logic Class (ELC) – Manages user interaction through console 📌 Key Features Implemented: ✅ Customer details management (Name, Address, Phone Number) ✅ Account balance handling ✅ Secure Deposit functionality with validation ✅ Safe Withdraw functionality with edge case handling ✅ Real-time balance display 🖥️ Execution Flow (ELC): ✔️ Took user input (Name, Address, Phone, Initial Deposit) ✔️ Created account using constructor ✔️ Displayed menu-driven options: 1️⃣ Withdraw 2️⃣ Deposit 3️⃣ Show Balance 4️⃣ Exit ✔️ Used loop to continuously interact until user exits ✔️ Handled invalid inputs with proper messages 💡 Concepts Practiced: ✔️ Constructors & Object Initialization ✔️ Encapsulation ✔️ Method Implementation ✔️ Looping (Menu-driven program) ✔️ Input Validation & Edge Case Handling ⚡ Special Focus: 🔸 Prevented invalid transactions (negative/zero values) 🔸 Avoided overdraft with "Insufficient Funds" check 🔸 Built a real-world console-based banking system 🎯 This project gave me a clear understanding of how backend logic works in banking applications and strengthened my Java fundamentals. I’m continuously learning and building projects as part of my journey to become a Full Stack Developer 🚀 #Java #OOP #BankApplication #Coding #Developer #JavaDeveloper #LearningJourney #100DaysOfCode

🚀 Built a Banking Management System using Python OOPs Happy to share one of my hands-on Python projects where I designed a Banking Management System by applying core Object-Oriented Programming concepts. This project simulates real-world banking operations and strengthened my understanding of writing structured, reusable, and scalable code. 🔹 Key functionalities ✔️ Account creation with auto-generated account number ✔️ Deposit and withdrawal operations ✔️ Balance inquiry ✔️ Customer details display ✔️ Minimum balance validation ✔️ Menu-driven user interaction 🔹 Concepts implemented ✅ Abstraction using "ABC" and "@abstractmethod" ✅ Inheritance ✅ Encapsulation ✅ Class variables ✅ Dictionaries and list-based data storage ✅ Conditional logic and loop handling ✅ User input validation This project gave me practical exposure to how OOP principles can be used to model real-world systems efficiently. Looking forward to building more real-world Python projects and continuously strengthening my software development skills with #10000Coders. 🚀 #Python #OOP #PythonProjects #SoftwareDevelopment #CodingJourney #VSCode #Programming #LinkedInProjects #Developer #10000Coders

🚀 Built a Student Management System using Java, JDBC, and SQL. This project includes: - Student Registration & Profile Management - Course Enrollment System - Grade Management - Admin Dashboard for Course CRUD Operations - Batch Execution for Multiple Records - Stored Procedures Integration - Transaction Management Through this project, I improved my understanding of: - JDBC Connectivity - PreparedStatement & CallableStatement - Database Design & Relationships - CRUD Operations - Batch Processing - Exception Handling Tech Stack: Java | JDBC | SQL | PostgreSQL Source code : https://lnkd.in/dPi--iZh Excited to keep building more real-world backend projects and grow as a Java Developer. #Java #JDBC #SQL #BackendDevelopment #Programming #JavaDeveloper