Under the Hood: Engineering Bulletproof Java Applications

Most Java developers spend their careers in the “user space” of APIs and frameworks, yet the most elusive production bugs and performance bottlenecks live in the “engine space” of the JVM. To build truly bulletproof systems, we must move beyond syntax and understand the mechanical sympathy between our code and the virtual machine.

This 1/2 day workshop strips away the abstractions to explore the internal mechanisms that dictate how Java applications actually execute. We will move past basic garbage collection and generics to tackle the sophisticated subsystems that define modern Java performance and stability.

Key learning pillars include:

The JIT Contract: How the C2 compiler uses speculative optimization and method inlining to turn bytecode into high-performance machine code—and how “deoptimization” can unexpectedly tank your throughput.

The Memory Model (JMM) & Concurrency: Why “thread-safe” code often isn't. We will decode the Happens-Before relationship and memory barriers to ensure data consistency across multi-core architectures.

Mechanical Sympathy with NIO: Moving beyond blocking I/O to leverage Selectors and Zero-Copy buffers for massive scalability.

ClassLoader Isolation: Mastering the delegation model to architect plugin-based systems and resolve complex “Dependency Hell” at runtime.

Attendees will leave with a mental model of the JVM’s internal decision-making process, allowing them to write code that is not just functional, but optimized for the hardware it runs on.

About Simon Roberts

Simon Roberts wrote his first program in 1978 in high school on punched cards. He started his career as a programmer building embedded control systems in a variety of assembly languages, C, and C++. Alongside programming, Simon taught part-time at a local college. In 1994 his career transitioned to full-time teacher and part time programmer, and he joined Sun Microsystems in 1995 where he worked until going independent in 2004

While at Sun he created training courses on a diverse range of Java topics, developed the original Sun Certified Java Programmer and Developer exams, and presented at JavaOne and other conferences on Java and Java performance topics.

Today, Simon is president of Dancing Cloud Services, LLC., based in Westminster Colorado, and he provides training, course development, and mentoring services in Java, Scala, JavaScript, Python, Go, along with design, and software architecture topics. Simon is equally comfortable offering training in classroom, recorded video, and live, remote-access, formats.

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