Java 27: G1 Becomes Default, Post-Quantum Security Arrives, and Compact Headers Land

Java 27: What's New?

I explore the key updates in Java 27, where G1 is now the default garbage collector across all environments and post-quantum hybrid key exchanges secure TLS 1.3. Compact object headers are enabled by default to boost performance, while JFR introduces automatic data redaction for sensitive information. Although no features exited preview this cycle, significant enhancements to Lazy Constants, Structured Concurrency, and the Vector API continue to evolve.

"It is rare enough to highlight that no features came out of preview in this release, as some long-standing features remain blocked waiting for the Valhalla project."