JDK 27 ships on Tuesday with a six-month lifespan. Ignoring it is the intended use.
OpenJDK puts Java 27's general availability at September 15; Temurin already lists its end: March 2027. On the cadence that made most Java versions optional, and two features worth reading.
Java 27 reaches general availability on 15 September, per the OpenJDK project schedule, which has tracked to the day through rampdown in June, the release-candidate build on 20 August, and now the ship date. The version's retirement is also already published: the Adoptium support table lists Temurin 27 builds ending in March 2027, when JDK 28 arrives. Six months, on schedule, by design.
That design is the story, eleven years after it would have been news. Since 2018 the platform has shipped a feature release every six months, with a long-term support version every two years; 25 is the current LTS, supported by Temurin until at least September 2031, and 27 is one of the three interim releases between it and the next LTS. An estate that runs the LTS line is not behind for skipping 27. It is using the cadence as published.
The dispatch would end there if the interim releases carried nothing, but they are where the platform's changes land first, and two of 27's listed features are worth the read even for estates that will never install it. JEP 523 makes G1 the default garbage collector in all environments, retiring the last cases where a JVM picked the older collector on small machines, which previews a default the next LTS will inherit. And JEP 527 adds post-quantum hybrid key exchange for TLS 1.3, the JDK's step in the same migration the browsers and CDNs began, arriving first in a release most production estates will read about rather than run.
That is what the six-month train is for. The interim releases are where defaults change while the blast radius is small, and the LTS inherits the results two years tested. Reading their release notes is how an estate learns what its next LTS will do before the LTS does it.
Builder's read: nothing to upgrade on Tuesday unless the team deliberately rides the release train, and teams that do already know. For everyone else, the twenty minutes is better spent reading 27's feature list as a preview of the next LTS, and checking that the current one is actually the version in production, because the estates that get burned by the cadence are never the ones on the LTS. They are the ones that stopped on an interim release in 2024 and called it done, and the retirement date on an interim release was six months from the day it shipped.