A high-performance concurrent bidding engine wrapped in a production-grade enterprise platform.
FORGE is a real-time online auction platform where sellers list items, bidders compete in live auctions, and the system handles concurrent bid matching, settlement, and wallet management — processing hundreds of thousands of bids per second using lock-free data structures and Java 21 Virtual Threads.
forge/
├── forge-engine/ # Pure Java 21 — zero Spring dependencies
│ ├── BiddingEngine # ConcurrentSkipListMap + Virtual Threads
│ ├── PriceTracker # AtomicReference CAS loop — lock-free
│ ├── BidBook # O(log n) thread-safe ordered bid storage
│ ├── AuctionStateMachine # ReentrantReadWriteLock state transitions
│ ├── EventBus # BlockingQueue pub/sub — Producer-Consumer
│ └── SettlementCalculator # Fee + tax computation
│
└── forge-platform/ # Spring Boot 3.2 — wraps the engine
├── REST API # JWT-secured endpoints
├── WebSocket # STOMP real-time bid feed
├── PostgreSQL # JPA + Hibernate 6 + Flyway migrations
├── Redis # Distributed caching
├── Quartz # DB-backed persistent job scheduling
└── MinIO # S3-compatible image storage
Why two modules? The engine is pure Java — no annotations, no DI framework. It can be embedded in any Java application. The platform wraps it with Spring Boot for REST, security, and persistence. ArchUnit enforces this separation automatically on every build.
| Layer | Technology |
|---|---|
| Language | Java 21 (Virtual Threads, Records, Sealed Classes) |
| Framework | Spring Boot 3.2 |
| Database | PostgreSQL 16 |
| Migrations | Flyway |
| Cache | Redis 7 |
| Scheduler | Quartz (DB-backed, crash-safe) |
| File Storage | MinIO (S3-compatible) |
| Security | Spring Security 6 + JWT |
| Real-time | WebSocket + STOMP |
| Testing | JUnit 5 + Mockito + ArchUnit |
| Benchmarks | JMH |
| Coverage | JaCoCo (80%+) |
| Build | Maven multi-module |
| Metric | Result |
|---|---|
| JMH Throughput | 400K–700K ops/sec (8 threads) |
| Concurrency Stress | 1000 virtual threads, 0 failures |
| Total Tests | 128 passing, 0 failures |
| JaCoCo Coverage | 80%+ |
| Architecture Rules | All passing (ArchUnit) |
| Pattern | Implementation |
|---|---|
| Strategy | PricingStrategy → English, Dutch, Sealed auction types |
| Observer | EventBus + EngineEventListener → WebSocket, DB bridge |
| State | AuctionStateMachine with validated transitions |
| Producer-Consumer | LinkedBlockingQueue in EventBus |
| CAS Loop | PriceTracker — lock-free price updates |
| Builder | Auction creation |
- Java 21+
- Maven 3.9+
- Docker (for PostgreSQL, Redis, MinIO)
# PostgreSQL
docker run -d --name postgres-forge \
-e POSTGRES_DB=forge_db \
-e POSTGRES_USER=postgres \
-e POSTGRES_PASSWORD=sensei \
-p 5432:5432 postgres:16
# Redis
docker run -d --name redis-forge \
-p 6379:6379 redis:7-alpine
# MinIO
docker run -d --name minio-forge \
-p 9000:9000 -p 9001:9001 \
-e MINIO_ROOT_USER=sensei \
-e MINIO_ROOT_PASSWORD=sensei123 \
quay.io/minio/minio server /data --console-address ":9001"# Build engine firstcd forge-engine && mvn clean install
# Run platformcd ../forge-platform && mvn spring-boot:runAPI: http://localhost:8080/api/v1/
Swagger: http://localhost:8080/swagger-ui.html
MinIO UI: http://localhost:9001
POST /api/v1/auth/register Register user
POST /api/v1/auth/login Login → returns JWT
POST /api/v1/auctions Create auction
GET /api/v1/auctions/active List active auctions
GET /api/v1/auctions/active/paged List with pagination (?page=0&size=20)
DELETE /api/v1/auctions/{id} Delete auction
POST /api/v1/auctions/{id}/bid Place bid (REST)
WS /ws WebSocket STOMP endpoint
SUB /topic/auctions/{id} Subscribe to live bid feed
POST /api/v1/wallet/topup Add funds
GET /api/v1/wallet/balance Get balance
POST /api/v1/images/upload Upload auction image → returns MinIO URL
# All engine tests (pure Java, no Docker needed)cd forge-engine && mvn test# All platform testscd forge-platform && mvn test# Full test suite with coverage report
mvn clean verify
# View coverage: forge-platform/target/site/jacoco/index.htmlBid Request (1000 concurrent)
↓
Virtual Thread Pool (Java 21)
↓
AuctionStateMachine.isActive() — READ LOCK
↓
PriceTracker.updatePrice() — CAS Loop (lock-free)
↓
BidBook.addBid() — ConcurrentSkipListMap O(log n)
↓
EventBus.publish() — LinkedBlockingQueue (non-blocking)
↓
WebSocket broadcast + DB persist (async)
forge-engine/src/
├── main/java/com/forge/engine/
│ ├── bidding/ BiddingEngine, BidBook
│ ├── event/ EventBus, EngineEvent (sealed), BidPlacedEvent
│ ├── model/ Bid, BidKey, Money, AuctionStateMachine, BidResult
│ ├── pricing/ PricingStrategy, English/Dutch/SealedBidPricing
│ ├── settlement/ SettlementCalculator, FeeCalculator, SettlementResult
│ └── tracker/ PriceTracker (AtomicReference CAS)
└── test/java/com/forge/engine/
├── architecture/ EngineArchitectureTest (ArchUnit)
├── benchmark/ BiddingEngineBenchmark (JMH)
├── bidding/ BidBookTest, BiddingEngineConcurrencyTest
├── model/ MoneyTest, AuctionStateMachineTest
└── settlement/ FeeCalculatorTest
forge-platform/src/
├── main/java/com/forge/platform/
│ ├── config/ Security, Redis, Quartz, MinIO, Engine wiring
│ ├── controller/ Auth, Auction, Bid, Wallet, Image, User
│ ├── entity/ User, Auction, Bid, Wallet
│ ├── service/ AuctionService, WalletService, AuthService, BidService
│ ├── repository/ JPA repositories with custom JPQL queries
│ ├── scheduler/ Quartz jobs (AuctionLifecycleJob)
│ ├── security/ JWT filter, token service
│ ├── bridge/ Engine ↔ Platform (DatabaseBridge, WebSocketBridge)
│ └── exception/ GlobalExceptionHandler
└── test/ 128 tests — service, controller, repository, arch
PII Masker Spring Boot Starter — auto-masks Aadhaar/PAN numbers in logs
<dependency>
<groupId>io.github.ketansinghrajput</groupId>
<artifactId>pii-masker-spring-boot-starter</artifactId>
<version>1.0.1</version>
</dependency>
Ketansingh Rajput — System Engineer Intern @ EdgeVerve Systems (Infosys)
B.E. Electronics & Telecommunication — SPPU 2025