Senior Java Developer – Spring Boot, Microservices & Multithreading (W2 ONLY)
** W2 ONLY - NO C2C - NO VISA SPONSORSHIP AVAILABLE ** Senior Java Developer - Spring Boot, Microservices & Multithreading (W2 ONLY)
Location: Englewood Cliffs, NJ
Duration: Long-Term, Ongoing Contract
Experience: 8+ Years
Position Type: Contract
Work Arrangement:
Hybrid - 3 days a week onsite About the Opportunity We are seeking a highly skilled Senior Java Developer to join the engineering team of a leading media and technology organization. The ideal candidate will have deep expertise in Core Java, Spring Boot, microservices architecture, multithreading, and high-performance backend application development. This role involves designing, developing, and optimizing scalable, reliable, and high-throughput backend services supporting complex, data-intensive enterprise applications. We are looking for a technically strong, hands-on engineer who understands Java internals, concurrent programming, distributed systems, and production-level performance optimization.
Key Responsibilities:
- Design, develop, and maintain high-performance backend applications using Java and Spring Boot.
- Build scalable, resilient microservices and RESTful APIs.
- Develop and optimize multithreaded and concurrent Java applications.
- Implement efficient asynchronous processing and parallel execution mechanisms.
- Design backend services capable of processing large volumes of data with low latency and high throughput.
- Apply distributed systems principles to ensure application scalability, reliability, and fault tolerance.
- Optimize application performance, memory utilization, JVM behavior, and database interactions.
- Troubleshoot complex production issues involving concurrency, thread contention, memory leaks, and performance bottlenecks.
- Collaborate with architects, engineering teams, and business stakeholders to translate requirements into robust technical solutions.
- Participate in architecture discussions, technical design reviews, and code reviews.
- Write clean, maintainable, well-tested production-quality code. Required Technical Skills Core Java & Concurrency 8+ years of professional Java development experience.
- Strong hands-on experience with Java 11/17/21 or newer.
- Excellent understanding of Java collections, generics, streams, and functional programming.
- Deep knowledge of multithreading, concurrency, synchronization, and thread safety.
- Experience with Executor
- Service, Completable
- Future, thread pools, concurrent collections, and asynchronous programming.
- Strong understanding of JVM internals, garbage collection, memory management, and performance tuning. Spring Boot & Microservices Extensive hands-on experience with Spring Boot and the Spring ecosystem.
- Proven experience designing and developing microservices-based applications.
- Strong knowledge of REST APIs, service-to-service communication, and API design.
- Understanding of distributed transactions, resilience patterns, circuit breakers, retries, and fault tolerance.
- Experience building scalable, highly available backend services. Performance & Distributed Systems Experience developing high-throughput, low-latency applications.
- Strong understanding of concurrent processing, asynchronous workflows, and event-driven architectures.
- Ability to identify and resolve performance bottlenecks.
- Experience with distributed caching, messaging, and data processing systems.
- Strong debugging, profiling, and production troubleshooting skills. Databases & Development Tools Strong SQL skills and experience with relational databases such as PostgreSQL, Oracle, or MySQL.Experience with database query optimization and performance tuning.
- Proficiency with Git, Maven/Gradle, and automated testing frameworks.
- Experience with CI/CD pipelines and modern software engineering practices. Preferred / Nice-to-Have Skills Experience with market data, financial data, real-time data feeds, or other data-intensive platforms.
- Hands-on experience with Kafka or similar event-streaming technologies.
- Experience with Redis or other distributed caching solutions.
- Familiarity with Kubernetes, Docker, and cloud platforms such as AWS.Experience with reactive programming frameworks.
- Understanding of messaging systems, event processing, and data ingestion pipelines.
- Experience building systems requiring high availability, low latency, and continuous data processing.
What We're Looking For:
This is a hands-on senior engineering position, not primarily a team management or coordination role. The successful candidate should be comfortable: Writing complex Java code independently.
Designing and troubleshooting multithreaded applications.
Explaining concurrency concepts and their practical implementation.
Building production-grade Spring Boot microservices.
Solving complex performance and scalability challenges.
Understanding architectural trade-offs in distributed systems.
Taking technical ownership of backend components from design through production. Candidates with strong Core Java fundamentals, practical multithreading experience, and deep Spring Boot/microservices expertise will be prioritized.