JDK 25 has arrived, bringing a major set of performance gains over JDK 21—often letting your existing, unchanged Java applications run faster right away. In this talk, we’ll dive into 13 concrete performance improvements delivered between JDK 21 and…

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A conference talk from Jfokus 2026 covering 13 concrete performance improvements in JDK 25 compared to JDK 21, spanning standard libraries, the JIT compiler, and garbage collectors. The presentation explores design tradeoffs behind these optimizations and how JDK engineers evaluate real-world performance. It also highlights the new preview feature Stable Value, which allows a field to combine benefits of both mutable and immutable data for potential speedups in existing applications.

Java Performance Update: From JDK 21 to JDK 25 – Inside.java