Marcus Vance
Lead Java / Enterprise Backend Engineer
Professional Summary
Senior Java Engineer with 7+ years architecting enterprise microservices and event-driven distributed systems using Java 17/21, Spring Boot 3.x, and Apache Kafka. Proven track record of scaling core banking services to 22,000 transactions per second (TPS), tuning JVM memory and ZGC pauses below 10ms, and migrating legacy monolithic JEE applications to cloud-native Kubernetes workloads on AWS. Dedicated champion of Testcontainers-driven integration testing and Domain-Driven Design (DDD).
Technical Skills
Work Experience
- •Architected distributed payment ledger microservices using Java 21, Spring Boot 3.2, and Spring Cloud, processing over $40M in daily transaction volume across 6 financial institutions.
- •Engineered event-driven transaction settlement pipelines utilizing Apache Kafka with idempotent consumers and dead-letter topics (DLT), slashing end-of-day settlement batch windows by 62%.
- •Tuned JVM heap allocation and migrated production services from G1GC to ZGC, reducing stop-the-world garbage collection pauses from 210ms to under 8ms during peak market open volatility.
- •Adopted Java 21 Virtual Threads (Project Loom) for high-concurrency external credit verification calls, boosting server throughput by 3.8x while reducing EC2 compute footprint by 28%.
- •Instituted zero-regression integration testing using Testcontainers with live PostgreSQL and Kafka containers, raising branch coverage to 91% across 14 microservice repositories.
- •Modernized legacy WebLogic application into 9 containerized Spring Boot microservices deployed on AWS EKS, reducing deployment cycle times from 3 weeks to bi-daily releases.
- •Optimized Hibernate/JPA query strategies, resolving catastrophic N+1 query patterns and introducing Redis second-level caching to decrease database p99 query latency from 850ms to 42ms.
- •Designed and implemented OAuth2 / OpenID Connect authorization servers using Spring Security and JWT, securing REST endpoints against unauthorized multi-tenant data access.
- •Automated database schema versioning across 4 distinct environments using Liquibase, preventing configuration drift and eliminating production rollback incidents over a 24-month period.
- •Mentored team of 6 junior and mid-level software engineers on Clean Architecture, effective concurrency patterns, and SonarQube static code quality metrics.
Selected Technical Projects
High-throughput API gateway middleware module providing distributed token-bucket rate limiting and cryptographically signed idempotency keys.
- •Engineered Redis Lua scripts for atomic token-bucket decrement operations, sustaining 45,000 requests per second with sub-5ms overhead.
- •Published reusable Spring Boot starter artifact to internal enterprise Nexus repository, utilized across 18 backend engineering teams.
Automated operational CLI and REST service for inspecting poisoned Kafka payloads, re-encrypting records, and orchestrating targeted topic replay.
- •Decreased mean time to resolution (MTTR) for malformed payload outages from 4 hours to under 12 minutes.
- •Implemented strict audit logging and schema registry verification via Confluent Avro schemas.
Education
University of Illinois Urbana-Champaign, Urbana, IL (2014 - 2018)
Specialization in Distributed Computing and Systems Architecture.
Certifications
- Oracle Certified Professional: Java SE 17 Developer
- AWS Certified Solutions Architect – Associate (SAA-C03)
- Confluent Certified Developer for Apache Kafka (CCDAK)
