Java 27 is currently in rampdown phase one and will reach general availability on September, 15th, 2026. The release will consist of 9 JEPs.
What is in there?
Java 27 will consist of these JEPs.
JEP 523 G1 becomes the default GC everywhere
Simplifies Java’s garbage collection behavior by making the G1 Garbage Collector the default choice across all hardware, removing the old rule where small or single-core machines would automatically fall back to the Serial collector.
JEP 527 Post-quantum Hybrid Key Exchange for TLS 1.3
Introduces a hybrid key exchange for Java 27 that layers new quantum-resistant math (ML-KEM) on top of proven traditional encryption to ensure data remains secure.
JEP 531 Lazy Constants
Delivers a third preview pass for Java 27’s Lazy Constants API, focusing on polishing the deferred immutability feature rather than completely reinventing it.
JEP 532 Primitive types in patterns
Another round of review for primitives in patterns. Nothing new in this JEP, it is just asking the community for feedback.
JEP 533 Structured Concurrency, 7th preview The seventh review of the new structured concurrency API.
JEP 534 Compact Object Headers by Default
After proving successful in production for the two releases, Compact Object Headers will now become the default instead of an opt-in.
JEP 536 JFR In-process Data Redaction
JEP 537 Vector API, twelfth Incubator
Yet another round of review for the new Vector API, without any new features.
JEP 538 PEM Encodings for Cryptographic Objects
Third preview for this API withou any new features.