hotspot

JDK 27 introduces notable changes to HotSpot's stop-the-world garbage collectors, most significantly JEP 523 making G1 the default GC in all environments, alongside various improvements, refactorings, and bug fixes.

This article explains how HotSpot's C2 JIT compiler uses a 'known bits' abstraction to track which bits of an integer are definitely zero or one, enabling optimizations like eliminating redundant bitwise AND operations.

A Codex skill that analyzes codebases to identify performance hotspots such as loops, repeated lookups, and N+1 patterns.