Senior Java Developer (Low-Latency & JVM Performance) in London, United Kingdom

Join a global technology team developing high-performance, low-latency platforms supporting critical trading and real-time processing workflows. The project focuses on building event-driven and reactive Java systems designed to operate at high frequency with demanding latency and throughput requirements.

The environment combines advanced JVM performance engineering, concurrency, networking, and Linux optimization. The team works close to the hardware and operating-system level, optimizing memory utilization, network communication, and application performance to deliver highly efficient and reliable systems.

Responsibilities

Design and develop high-performance, low-latency applications using Core Java.

Perform advanced JVM profiling, GC analysis, and performance tuning to minimize latency and maximize throughput.

Build event-driven and reactive systems capable of processing high-frequency workloads.

Optimize concurrency, memory management, data structures, and algorithms for performance-critical applications.

Develop and optimize networking components using TCP/UDP and low-latency communication techniques.

Work with low-level Java technologies such as JNI, Java Unsafe, and JNR-FFI where required for performance optimization.

Analyze application and Linux system performance, identify bottlenecks, and implement improvements.

Collaborate with global engineering teams on architecture, development, testing, and production support.

Skills

Must have

8+ years of hands-on software development experience, with strong expertise in Core Java and performance-critical applications.

Strong experience with JVM performance engineering and tuning, including GC optimization, memory management, profiling, and latency analysis.

Excellent knowledge of multithreading, concurrency, data structures, algorithms, and algorithmic complexity.

Proven experience building low-latency, high-throughput, event-driven or reactive systems.

Strong knowledge of network programming and protocols, particularly TCP/UDP, and experience optimizing network-intensive applications.

Strong understanding of Linux internals and performance analysis in Linux environments.

Good understanding of CPU architecture and memory management, including shared memory, memory-mapped files, caches, and their impact on application performance.

Experience with low-level Java technologies such as JNI, Java Unsafe, JNR-FFI, or comparable native integration techniques.

Nice to have

Experience with Aeron for high-performance, low-latency messaging.

Experience with profiling, benchmarking, and latency analysis of high-performance Java applications.

Familiarity with native Java integration technologies, such as JNI, Java Unsafe, or JNR-FFI, beyond basic working knowledge.

Exposure to hardware-aware performance optimization in latency-sensitive applications.

Previous experience in real-time, high-frequency, or performance-critical application environments.

Other

Languages

English: B2 Upper Intermediate

Seniority

Senior