Oracle has finalized the JDK 27 feature set with nine new capabilities, launching September 15. The biggest shift is making Garbage-First (G1) the default garbage collection mechanism across all execution environments, moving beyond its previous limitation to large-scale server deployments. This change brings automatic memory management improvements to applications of all sizes.
Memory efficiency gets a boost through a new compact object header structure enabled by default, reducing heap consumption and improving data processing speed on modern servers. On the security front, JDK 27 introduces post-quantum hybrid key exchange in TLS 1.3, blending traditional encryption algorithms with protections designed to defend against future quantum computing attacks. The platform's diagnostic utility now automatically masks passwords, API keys, and access tokens in environment variables before system reports are generated, preventing credential exposure.
Language enhancements include lazy constant initialization to conserve resources, improved concurrent task execution, and expanded support for primitive data types. As a short-term support (non-LTS) release, JDK 27 will receive official Oracle support for six months only.
