JDK 25 has just been released and is packed with performance improvements compared to JDK 21, allowing your unchanged application code to run even faster.

In this talk, we will take a closer look at 13 concrete performance improvements made between JDK 21 and JDK 25 involving both the standard Java libraries, the JIT compiler, and the garbage collectors. Among these improvements is the newly introduced Stable Value preview feature, which allows a field to share the benefits of both mutable and immutable fields simultaneously. We will learn how this new feature works, how much performance can be improved, and how your code can take advantage of it already today. We will also explore some of the design considerations made, the importance of developer feedback, and how the JDK engineers evaluate performance in a world of conflicting optimization criteria and varying platform properties.

Recorded at Devoxx Belgium 2025.