JDK 27, the reference implementation of Java 27, has reached General Availability after build 35 passed as the second release candidate with no critical bugs found. The release bundles nine JDK Enhancement Proposals, including G1 as the default garbage collector everywhere, post-quantum hybrid key exchange for TLS 1.3, compact object headers by default, and further previews of structured concurrency and pattern matching features. Oracle's GPL-licensed OpenJDK builds are already available for download, with other vendors expected to follow.
mail.openjdk.org
· 2026-09-15
A JMH benchmark filling two reference arrays showed drastically different results depending on garbage collector: about 0.5ms on ParallelGC versus 139ms on G1GC, despite no garbage collection occurring during the measured operations. The author traces this gap through JIT compilation and JVM flags down to a specific machine instruction responsible for the slowdown.
krzysztofslusarski.github.io
· 2026-09-01
JDK 28 has integrated JEP 401, a Project Valhalla milestone, as a preview feature that introduces value classes to the JVM. The author explains that these classes drop object identity, letting the JVM flatten and scalarize data in memory rather than always using pointer-based references, which can boost performance in many cases.
johan-sjolen.github.io
· 2026-08-26
GoKawiil