Programmer1970

Jun 1, 2026 · Fundamentals

Why ZGC Pauses Stay Under 1 ms: Inside Colored Pointers and Load Barriers

The article explains how ZGC achieves sub‑millisecond pause times by embedding GC state in pointer bits (colored pointers) and using JIT‑injected load barriers that fix references on first access, comparing this approach with G1 and Shenandoah and detailing ZGC 2.0 enhancements and known pitfalls.