Re: JDK 21 EA builds 22 & Sequenced Collections Heads-up
Hello David, I ran the Ant testsuite against Java 21 EA build 21-ea+22-1890 and all tests went fine without any failures https://ci-builds.apache.org/job/Ant/job/Ant%20Master%20Linux%20(latest%20EA%20JDK)/35/ -Jaikiran On 15/05/23 8:08 pm, David Delabassee wrote: Welcome to the latest OpenJDK Quality Outreach update! The proposed schedule for JDK 21 is now known [1] with Rampdown Phase One (RDP1) phase set for June 8th and General Availability (GA) set for September 19th. As we are getting closer to RDP1, we are gradually getting a better view on the JDK 21 content. At the time of writing, 5 JEPs are already integrated in the JDK 21 mainline - Virtual Threads, Generational ZGC, etc. – see below for more details. This newsletter heads-up is focused on one of those JEPs; i.e., JEP 431 Sequenced Collections, as it might induce some incompatibilities on existing codebases. Please do tell us if your project works or fails on the latest JDK 21 Early-Access builds. We still have some time to fix issues before JDK 21 reaches General Availability. [1] https://openjdk.org/projects/jdk/21/ ## Heads-Up - JDK 21: Potential Sequenced Collections Incompatibilities The Sequenced Collection JEP [2] has been integrated into JDK 21, build 20. This JEP introduces several new interfaces into the collections framework’s interface hierarchy, and these interfaces introduce new default methods. When such changes are made, they can cause conflicts that result in source or binary incompatibilities. Any conflicts that occur will be in code that implements new collections or that subclasses existing collection classes. Code that simply uses collections implementations will be largely unaffected. There are several kinds of conflicts that might arise. The first is a simple method naming conflict, if a method already exists with the same name but with a different return type or access modifier. Another is a clash between different inherited default method implementations arising from covariant overrides. A class might inherit multiple default methods if it implements multiple interfaces from different parts of the collections framework. A third example occurs with type inference. With type inference (e.g., the use of `var`) the compiler will infer a type for that local variable. It’s possible for other code to use explicitly declared types that must match the inferred type. The change to the interface hierarchy might result in a different inferred type, causing an incompatibility. Make sure to check the following article [3] that provides additional details and strategies to mitigate potential incompatibilities. [2] https://openjdk.org/jeps/431 [3] https://inside.java/2023/05/12/quality-heads-up/ Additional Sequenced Collections resources are also listed in the 'Topics of Interest' section below. ## JDK 21 Early-Access builds The latest Early-Access builds 22 are available [4], and are provided under the GNU General Public License v2, with the Classpath Exception. The Release Notes [5] and the Javadocs [6] are also available. [4] https://jdk.java.net/21/ [5] https://jdk.java.net/21/release-notes [6] https://download.java.net/java/early_access/jdk21/docs/api/ ### JEPs integrated to JDK 21, so far: - 430: String Templates (Preview) - 431: Sequenced Collections - 439: Generational ZGC - 442: Foreign Function & Memory API (3rd Preview) - 444: Virtual Threads ### JEPs targeted to JDK 21, so far: - 440: Record Patterns - 441: Pattern Matching for switch - 448: Vector API (6th Incubator) JEPs proposed to target JDK 21: - 404: Generational Shenandoah (Experimental) - 443: Unnamed Patterns and Variables (Preview) - 445: Unnamed Classes and Instance Main Methods (Preview) - 449: Deprecate the Windows 32-bit x86 Port for Removal ### Changes in recent builds that may be of interest: Note that this is only a curated list of changes, make sure to check https://github.com/openjdk/jdk/compare/jdk-21+0...jdk-21+22 for additional changes. JDK 21 Build 22: - JDK-8307466: java.time.Instant calculation bug in until and between methods - JDK-8307399: get rid of compatibility ThreadStart/ThreadEnd events for virtual threads - JDK-8306461: ObjectInputStream::readObject() should handle negative array sizes without throwing NegativeArraySizeExceptions - JDK-8280031: Deprecate GTK2 for removal - JDK-8307629: FunctionDescriptor::toMethodType should allow sequence layouts (mainline) - JDK-8302845: Replace finalizer usage in JNDI DNS provider with Cleaner - JDK-8306461: ObjectInputStream::readObject() should handle negative array sizes without throwing NegativeArraySizeExceptions - JDK-8306881: Update FreeType to 2.13.0 - JDK-8285932: Implementation of JEP 430 String Templates (Preview) - JDK-8307301: Update HarfBuzz to 7.2.0 - JDK-8159337: Introduce a method in Locale class to return the language tags as per RFC 5646 convention - JDK-8291555: Implement alternative fast-locking scheme - JDK-8305486: Add
JDK 21 EA builds 22 & Sequenced Collections Heads-up
Welcome to the latest OpenJDK Quality Outreach update! The proposed schedule for JDK 21 is now known [1] with Rampdown Phase One (RDP1) phase set for June 8th and General Availability (GA) set for September 19th. As we are getting closer to RDP1, we are gradually getting a better view on the JDK 21 content. At the time of writing, 5 JEPs are already integrated in the JDK 21 mainline - Virtual Threads, Generational ZGC, etc. – see below for more details. This newsletter heads-up is focused on one of those JEPs; i.e., JEP 431 Sequenced Collections, as it might induce some incompatibilities on existing codebases. Please do tell us if your project works or fails on the latest JDK 21 Early-Access builds. We still have some time to fix issues before JDK 21 reaches General Availability. [1] https://openjdk.org/projects/jdk/21/ ## Heads-Up - JDK 21: Potential Sequenced Collections Incompatibilities The Sequenced Collection JEP [2] has been integrated into JDK 21, build 20. This JEP introduces several new interfaces into the collections framework’s interface hierarchy, and these interfaces introduce new default methods. When such changes are made, they can cause conflicts that result in source or binary incompatibilities. Any conflicts that occur will be in code that implements new collections or that subclasses existing collection classes. Code that simply uses collections implementations will be largely unaffected. There are several kinds of conflicts that might arise. The first is a simple method naming conflict, if a method already exists with the same name but with a different return type or access modifier. Another is a clash between different inherited default method implementations arising from covariant overrides. A class might inherit multiple default methods if it implements multiple interfaces from different parts of the collections framework. A third example occurs with type inference. With type inference (e.g., the use of `var`) the compiler will infer a type for that local variable. It’s possible for other code to use explicitly declared types that must match the inferred type. The change to the interface hierarchy might result in a different inferred type, causing an incompatibility. Make sure to check the following article [3] that provides additional details and strategies to mitigate potential incompatibilities. [2] https://openjdk.org/jeps/431 [3] https://inside.java/2023/05/12/quality-heads-up/ Additional Sequenced Collections resources are also listed in the 'Topics of Interest' section below. ## JDK 21 Early-Access builds The latest Early-Access builds 22 are available [4], and are provided under the GNU General Public License v2, with the Classpath Exception. The Release Notes [5] and the Javadocs [6] are also available. [4] https://jdk.java.net/21/ [5] https://jdk.java.net/21/release-notes [6] https://download.java.net/java/early_access/jdk21/docs/api/ ### JEPs integrated to JDK 21, so far: - 430: String Templates (Preview) - 431: Sequenced Collections - 439: Generational ZGC - 442: Foreign Function & Memory API (3rd Preview) - 444: Virtual Threads ### JEPs targeted to JDK 21, so far: - 440: Record Patterns - 441: Pattern Matching for switch - 448: Vector API (6th Incubator) JEPs proposed to target JDK 21: - 404: Generational Shenandoah (Experimental) - 443: Unnamed Patterns and Variables (Preview) - 445: Unnamed Classes and Instance Main Methods (Preview) - 449: Deprecate the Windows 32-bit x86 Port for Removal ### Changes in recent builds that may be of interest: Note that this is only a curated list of changes, make sure to check https://github.com/openjdk/jdk/compare/jdk-21+0...jdk-21+22 for additional changes. JDK 21 Build 22: - JDK-8307466: java.time.Instant calculation bug in until and between methods - JDK-8307399: get rid of compatibility ThreadStart/ThreadEnd events for virtual threads - JDK-8306461: ObjectInputStream::readObject() should handle negative array sizes without throwing NegativeArraySizeExceptions - JDK-8280031: Deprecate GTK2 for removal - JDK-8307629: FunctionDescriptor::toMethodType should allow sequence layouts (mainline) - JDK-8302845: Replace finalizer usage in JNDI DNS provider with Cleaner - JDK-8306461: ObjectInputStream::readObject() should handle negative array sizes without throwing NegativeArraySizeExceptions - JDK-8306881: Update FreeType to 2.13.0 - JDK-8285932: Implementation of JEP 430 String Templates (Preview) - JDK-8307301: Update HarfBuzz to 7.2.0 - JDK-8159337: Introduce a method in Locale class to return the language tags as per RFC 5646 convention - JDK-8291555: Implement alternative fast-locking scheme - JDK-8305486: Add split() variants that keep the delimiters to String and j.u.r.Pattern JDK 21 Build 21: - JDK-8305092: Improve Thread.sleep(millis, nanos) for sub-millisecond granularity - JDK-8303784: no-@Target annotations should be applicable to type parameter declarations -
