--- title: JDK 27 features & release date: what Java devs need to know description: JDK 27, shipping September 15, 2026, finalizes several JEPs: post-quantum ML-KEM key encapsulation built into TLS 1.3 (JEP 527), G1 as the default garbage... canonical: https://daily.dev/posts/jdk-27-features-release-date-what-java-devs-need-to-know-aaaism2vc twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: JDK 27 features & release date: what Java devs need to know | daily.dev og:description: JDK 27, shipping September 15, 2026, finalizes several JEPs: post-quantum ML-KEM key encapsulation built into TLS 1.3 (JEP 527), G1 as the default garbage... og:url: https://daily.dev/posts/jdk-27-features-release-date-what-java-devs-need-to-know-aaaism2vc og:image: https://api.daily.dev/og/posts/AaaISm2vC.png og:image:alt: JDK 27 features & release date: what Java devs need to know og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # JDK 27 features & release date: what Java devs need to know **[FireUp](https://daily.dev/sources/fireup-pro)** · 3 min read · 0 upvotes · 0 comments ## Summary JDK 27, shipping September 15, 2026, finalizes several JEPs: post-quantum ML-KEM key encapsulation built into TLS 1.3 (JEP 527), G1 as the default garbage collector everywhere (JEP 523), and compact object headers enabled by default (JEP 534), cutting typical heap usage 10-20%. Structured Concurrency reaches its seventh preview (JEP 533), primitive pattern matching its fifth (JEP 532), and PEM encoding APIs their third preview (JEP 538). Looking ahead, JDK 28 (March 2027) is expected to add a built-in Simple JSON API (JEP 540), Value Objects from Project Valhalla (JEP 401), generational Shenandoah GC by default, and Strict Field Initialization (JEP 539). Early access builds for both JDK 27 and JDK 28 are already available. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### When does JDK 27 release and what are its main new features? JDK 27 ships September 15, 2026. Its headline features are post-quantum cryptography in TLS 1.3 via ML-KEM key encapsulation (JEP 527, following NIST FIPS 203), G1 becoming the default garbage collector everywhere including containers (JEP 523), and compact object headers enabled by default (JEP 534), shrinking most object headers from 16 bytes to 8 bytes and cutting heap usage 10-20% on typical workloads. _daily.dev helps java teams planning JVM upgrades stay ahead of JDK 27's default changes._ ### How much heap memory do compact object headers save in JDK 27? Compact object headers, enabled by default via JEP 534, reduce object header size from 16 bytes to 8 bytes for most objects, cutting overall heap usage by roughly 10-20% on typical workloads. This feature was opt-in and experimental in JDK 26. Applications with millions of small objects, such as caches, message queues, and graph structures, benefit most from the reduction. _track JVM memory tuning changes like this on daily.dev before rolling out a Java upgrade._ ### What is the Simple JSON API coming in JDK 28? JEP 540 adds a standard JSON parsing and generation API to the JDK, covering JsonValue, JsonObject, JsonArray, and basic serialization, with no external library required. It targets simple cases like parsing a config file or webhook payload rather than replacing Jackson for complex mapping. JDK 28 is expected in March 2027, and early access builds already include the API. _java developers weighing JDK 28 upgrades can follow API changes like this on daily.dev._ --- Tags: [#java](https://daily.dev/tags/java), [#quantum-computing](https://daily.dev/tags/quantum-computing) [View this post on daily.dev](https://daily.dev/posts/jdk-27-features-release-date-what-java-devs-need-to-know-aaaism2vc) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"JDK 27 features & release date: what Java devs need to know","url":"https://daily.dev/posts/jdk-27-features-release-date-what-java-devs-need-to-know-aaaism2vc","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/jdk-27-features-release-date-what-java-devs-need-to-know-aaaism2vc"},"datePublished":"2026-08-25T08:22:30.218Z","dateModified":"2026-09-13T21:11:17.952Z","description":"JDK 27, shipping September 15, 2026, finalizes several JEPs: post-quantum ML-KEM key encapsulation built into TLS 1.3 (JEP 527), G1 as the default garbage...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/0423a577e81b7dbd121d77d2b7d6da46?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/0423a577e81b7dbd121d77d2b7d6da46?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"FireUp","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"FireUp","logo":"https://media.daily.dev/image/upload/s--JWZsm71i--/f_auto,q_auto/v1774960866/logos/fireup-pro?_a=BAMAMiWQ0","url":"https://daily.dev/sources/fireup-pro"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/jdk-27-features-release-date-what-java-devs-need-to-know-aaaism2vc","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"java,quantum-computing","timeRequired":"PT3M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"FireUp","item":"https://daily.dev/sources/fireup-pro"},{"@type":"ListItem","position":3,"name":"JDK 27 features & release date: what Java devs need to know"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/jdk-27-features-release-date-what-java-devs-need-to-know-aaaism2vc#faq","mainEntity":[{"@type":"Question","name":"When does JDK 27 release and what are its main new features?","acceptedAnswer":{"@type":"Answer","text":"JDK 27 ships September 15, 2026. 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