Vijay Kumar — Java Backend Engineer

Profile

Backend Engineer specializing in Java 17 and Spring Boot 3 with extensive hands-on experience architectural-designing and deploying real-time distributed systems and automated CI/CD pipelines. Shipped Nexus, a production-live multiplayer platform capable of managing high-concurrency WebSocket sessions and persistent transactions. Proficient in concurrent data structures, database optimization, and high-fidelity production debugging. Seeking a remote backend software engineering position.

Technical Skills

- Languages: Java 17, SQL, JavaScript (ES2022), HTML5, CSS3

- Frameworks & Backend: Spring Boot 3, Spring Data JPA, Spring Security, REST APIs, WebSocket (STOMP/SockJS), JWT, bcrypt

- Databases & ORM: PostgreSQL, Hibernate ORM, JPQL, H2 Database

- DevOps & Cloud: Docker, GitHub Actions, Linux (Ubuntu), Oracle Cloud Infrastructure (OCI), systemd, Vercel, Render

- Tools & Foundations: Maven, JUnit 5, Mockito, Git, Raw Sockets, Multithreading, Clean Architecture, OOP, DSA

Projects

Nexus — Real-Time Multiplayer Game Platform

Live nexusgame.space GitHub

Java 17 · Spring Boot 3 · WebSocket (STOMP) · PostgreSQL · Spring Security · GitHub Actions · Oracle Cloud (Ubuntu VM)

Engineered high-concurrency game loop state utilizing ConcurrentHashMap and atomic operations, eliminating data races across active real-time sessions.
Architected custom WebSocket session lifecycle observers via STOMP/SockJS to handle connection state, user presence tracking, and room-scoped routing.
Diagnosed and resolved a critical production crash caused by a JPQL enum inner-class mapping error (User$UserStatus), converting it to a named parameter query and stopping game move dropouts.
Bypassed an outbound SMTP port-587 cloud block by decoupling JavaMailSender and implementing the Resend REST API over port 443, lowering mail delivery timeouts from 120s to <1s.
Implemented a secure authentication workflow with Spring Security, state-managed JWTs, bcrypt password hashing, and tokenized email activations.
Standardized a zero-touch CI/CD pipeline via GitHub Actions to run test suites, package executable JARs, transfer via SCP, and automatically restart the systemd daemon.

Portfolio Website & Engineering Log

Live vijaykumarcode.space GitHub

Vanilla JavaScript · HTML5 · CSS3 · PWA · Cloudflare Turnstile · Formspree · Vercel CDN Edge Network

Designed a framework-less Markdown-to-DOM compilation workflow for a technical blog, ensuring an instantaneous loading cycle and zero Cumulative Layout Shift (CLS).
Secured public-facing messaging routes by routing decoupled user interactions through Cloudflare Turnstile cryptographic verification and a serverless Formspree workflow.
Preconfigured progressive web app (PWA) cache-control rules to optimize service-worker asset retrieval directly across edge points.

TicTacToe — Network Multiplayer Engine

GitHub

Java · TCP Sockets · Multithreading · Concurrency

Created a low-level TCP socket-based multiplayer application server from scratch handling active client traffic via isolated worker threads.
Implemented multi-client thread pools and thread-safe shared states that structurally served as the architectural iteration proof for the Nexus WebSocket engine.

DSA in Java — Documented Algorithm Library

GitHub

Java 17 · Data Structures · Algorithms · Complexity Analysis

Authored a comprehensive repository of reference implementation files covering Trees, Graphs, custom Linked Lists, and advanced Sorting/Searching patterns.
Profiled and cataloged exact Time and Space complexities using Javadoc-style modular headers to adhere to strict engineering standards.

Education

Master of Computer Applications (MCA) Ajay Kumar Garg Engineering College (AKGEC) — Ghaziabad

Uttar Pradesh

Bachelor of Computer Applications (BCA) L.N. Mishra College of Business Management (LNMCBM) — Muzaffarpur

Bihar