The Latest in OpenJDK and JCP Expert Group: Insights with Simon Ritter

December 22, 2025·39 min·2 clips

Changing one rectangle from white to yellow triggered four million method calls — Simon Ritter's DTrace experiment reveals Java's hidden complexity.

The thread is practical from the start. Redlich introduces Ritter as deputy CTO for Zool and a member of the JDK26 expert group, then moves into the steady rhythm of JDK releases. From there, the interview settles into Java mechanics. Ritter describes the main problem as waste: services start, repeat the same loading and initialization steps, and pay that cost again. Graal gives teams one answer. It compiles Java into native instructions for a target platform, which can mean immediate startup and strong compiled-code performance. Ritter does not treat that as free. The closed-world model asks Java to give up some of the flexibility it usually gets from dynamic class loading. Reflection has to be made more explicit. That can be handled, but it adds work before the application ever runs. Leiden goes after the problem differently. Instead of compiling everything ahead of time, it asks which repeated work the runtime can avoid while still watching how the application behaves. Class loading is the first example. If the runtime already knows which classes need loading or initialization, it can skip familiar bookkeeping. Warmup still matters, though. Ritter keeps coming back to Java's later performance gains, which often come from speculative optimizations after the runtime sees real behavior. That is the clean split: Graal fixes more up front, while Leiden tries to keep more of Java's adaptive compilation story. Redlich frames startup time, microservices, and service replication as everyday engineering costs, not benchmark trivia. The close stays friendly, with a pointer to Ben Evans's earlier news piece dated 13 November last year, the lead editor handoff, and Java user groups around New York City, New Jersey, and Philly.

As heard by us

A practical OpenJDK discussion that turns Java startup, Graal, and Project Leiden into real engineering tradeoffs.

The InfoQ Podcast puts Simon Ritter, Azul deputy CTO and JDK 26 expert group member, in a useful conversation for engineers who follow Java closely.

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Why you'd press play

If you care how Java gets faster without giving up runtime flexibility.

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