Java Developer

Summary: The role of Senior Java Engineer focuses on developing low-latency systems with an emphasis on high-performance applications. The position requires expertise in Java NIO, event-driven architectures, and performance optimization techniques. The successful candidate will work on custom binary protocols and collaborate with architecture teams to enhance system efficiency. This is a six-month contract based in London with a flexible working arrangement.

Key Responsibilities:

• Designing and optimizing event-driven, non-blocking I/O systems using Java NIO
• Working with ByteBuffers and direct memory access techniques for optimal performance
• Developing and maintaining custom binary protocols, ideally with experience in SBE (Simple Binary Encoding)
• Integrating and fine-tuning Aeron messaging in high-frequency, low-latency environments
• Conducting performance benchmarking using JMH and other micro-benchmarking tools
• Tuning JVMs for real-time applications, including GC tuning (ZGC, Shenandoah) and lock-free/wait-free structures
• Collaborating closely with architecture teams to ensure garbage-free, latency-critical design

Key Skills:

• Core Low-Latency Engineering Experience
• Strong command of Java NIO, selectors, channels, and event loops
• Deep understanding of ByteBuffer usage, memory alignment, and off-heap data structures
• Experience with binary protocols (fixed-width encoding, custom parsers, etc.)
• Hands-on expertise with Aeron or similar low-latency transport layers
• Performance Engineering Knowledge
• Familiarity with threading models like epoll, reactor pattern
• Use of lock-free/wait-free data structures in production
• JVM internals expertise – GC tuning, heap sizing, latency profiling
• Benchmarking experience with JMH, latency histograms, flame graphs

Salary (Rate): 500

City: London

Country: United Kingdom

Working Arrangements: hybrid

IR35 Status: outside IR35

Seniority Level: Senior

Industry: IT