A region-based, mostly-concurrent garbage collector in Oracle's HotSpot JVM, designed to balance throughput and low pause times for Java applications.
JDK 27 drops the automatic fallback to Serial GC on limited hardware. A JVM in a tight container now gets G1 unless an operator asks for something else, and compact object headers move footprint in the same release.
Reality
Oracle's JDK 27 release notes put hybrid post-quantum key exchange for TLS 1.3 into the default configuration. The migration now belongs to whoever schedules the runtime upgrade.
Reality
JEP 527's hybrid key exchange landed as a stable feature on September 15, and the same JDK makes G1 the collector on small machines and cuts every object header to 64 bits. Serial is still one flag away.
Perspective Coverage
4 publishersReality
The non-LTS release is mostly two years of JDK 25 experiments switched on by default, and the flipped defaults change memory and handshake behaviour in small containers rather than adding syntax anyone will write.
Reality
The feature list is fixed until the September 15 ship date. Five items are previews you have to ask for; two are HotSpot defaults that apply whether you read the notes or not.
Reality