Java Tech Enthusiast

Aug 3, 2026 · Backend Development

JDK 27 Switches Default GC to G1—Why Your Unchanged Java Service Might Slow Down

JDK 27 changes the default garbage collector from a resource‑aware Serial GC to G1, which can unexpectedly increase CPU usage, alter latency and throughput for small‑container Java services even when no code or JVM flags are changed, so teams must verify the GC in use and benchmark both collectors under realistic limits.