Principal Java Engineer - JVM

Are you the kind of Senior Java Engineer who is an expert in the JVM and loves solving problems deep inside the runtime?

We’re looking for a seasoned technical heavyweight — a true master of the Java ecosystem — who lives and breathes bytecode, understands the guts of the JDK, and thrives on solving deep, complex problems in live systems. This is not your average Java dev role — this is a chance to get hands-on with the runtime itself and shape the architecture of high-impact cybersecurity products used across global enterprises.

What You'll Be Doing:

• Building and evolving bleeding-edge Java Agent technology used in modern runtime application security.

• Designing algorithms that dynamically transform running code to detect and neutralise threats in real-time.

• Working in the guts of the JVM — manipulating bytecode, exploring obscure APIs, and optimising performance under extreme conditions.

• Collaborating with elite engineers in a tight-knit R &D team where every line of code counts.

• Contributing to product innovation and setting best practices across engineering, security, and DevOps.

Requirements

✅ What You Bring:

• 10+ years of serious Java engineering experience — including JVM internals, JIT, garbage collection, and low-level optimisations.

• Expert in low-level Java, Java Virtual Machine
• Mastery of Java bytecode and classloading — you’ve probably written your own agents, class transformers, or custom instrumentation tools.

• Passion for secure software development and an instinct for rooting out vulnerabilities before they happen.

• Hands-on experience with complex debugging, performance tuning, and real-world system architecture.

• Confident communicator who thrives in a collaborative, intellectually curious environment.

⚙️ Nice-To-Haves:

• Familiarity with Groovy, Kotlin, Python, or TypeScript.

• Background in building developer tools or security products.

• Experience in mentoring or leading technical teams (or ambition to grow in that direction).

Benefits

If you are a strong very Senior Java Engineer up to Principal Engineer level or close it and you have the required Low-Level Java, JVM expertise, then please send your CV to Gerry Nolan at Stack and Co today via [gerry@stackand.co](mailto:gerry@stackand.co)

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