April 2025 - core-libs-dev

RFR: 8352171: Arrays.hashCode for sub-range of byte array API addition
by Zihao Lin 06 Mar '26

06 Mar '26

Add the java.util.Arrays.hashCode(byte[], int start, int end). Hi team, I am new here, please give me some guidance. Thank you. ------------- Commit messages: - 8352171: Arrays.hashCode for sub-range of byte array API addition Changes: https://git.openjdk.org/jdk/pull/24128/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24128&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8352171 Stats: 30 lines in 1 file changed: 30 ins; 0 del; 0 mod Patch: https://git.openjdk.org/jdk/pull/24128.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/24128/head:pull/24128 PR: https://git.openjdk.org/jdk/pull/24128

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RFR: 8347009: Speed up parseInt and parseLong
by Shaojin Wen 09 Feb '26

09 Feb '26

This is an optimization for decimal Integer.parseInt and Long.parseLong, which improves performance by about 10%. The optimization includes: 1. Improve performance by parsing 2 numbers at a time, which has performance improvements for numbers with length >= 3. 2. It uses charAt(0) for the first number. Assuming that the optimization can eliminate boundary checks, this will be more friendly to parsing numbers with length 1. 3. It removes the reliance on the Character.digit method and eliminates the reliance on the CharacterDataLatin1#DIGITS cache array, which avoids performance degradation caused by cache misses. ------------- Commit messages: - optimize parseInt & parseLong - optimize parseInt & parseLong - reuse isDigit - optimize parseInt - optimize parseLong - add benchmark Changes: https://git.openjdk.org/jdk/pull/22919/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22919&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8347009 Stats: 141 lines in 4 files changed: 65 ins; 16 del; 60 mod Patch: https://git.openjdk.org/jdk/pull/22919.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/22919/head:pull/22919 PR: https://git.openjdk.org/jdk/pull/22919

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RFR: 8337143: (fc, fs) Move filesystem-related native objects from libnio to libjava
by Brian Burkhalter 04 Feb '26

04 Feb '26

This proposed change would move the native objects required for NIO file interaction from the libnio native library to the libjava native library on Linux, macOS, and Windows. ------------- Commit messages: - 8337143: (fc, fs) Move filesystem-related native objects from libnio to libjava Changes: https://git.openjdk.org/jdk/pull/20317/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20317&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8337143 Stats: 1265 lines in 75 files changed: 631 ins; 523 del; 111 mod Patch: https://git.openjdk.org/jdk/pull/20317.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/20317/head:pull/20317 PR: https://git.openjdk.org/jdk/pull/20317

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RFR: 8333377: Migrate Generic Signature parsing to ClassFile API
by Chen Liang 30 Jan '26

30 Jan '26

Core reflection's generic signature parsing uses an ancient library with outdated visitor pattern on a tree model and contains unnecessary boilerplates. This is a duplication of ClassFile API's signature model. We should just move to ClassFile API, which is more throughoutly tested as well. To ensure compatibility, new tests are added to ensure consistent behavior when encountering malformed signatures or signatures with missing types. The reflective objects have been preserved and the only change is that lazy expansion now happens from CF objects, to reduce compatibility risks. ------------- Commit messages: - Remove redundant try-catch in getEnclosingMethod/Constructor - Merge branch 'test/signature-error' into feature/new-generic-info - Fix everything - Fixxes - Stage - Stage new tests - Merge branch 'master' of https://github.com/openjdk/jdk into feature/new-generic-info - Merge branch 'master' of https://github.com/openjdk/jdk into feature/new-generic-info - Merge branch 'master' of https://github.com/openjdk/jdk into feature/new-generic-info - Merge branch 'master' of https://github.com/openjdk/jdk into feature/new-generic-info - ... and 5 more: https://git.openjdk.org/jdk/compare/8aeada10...4110c13f Changes: https://git.openjdk.org/jdk/pull/19281/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19281&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8333377 Stats: 4605 lines in 66 files changed: 1027 ins; 3483 del; 95 mod Patch: https://git.openjdk.org/jdk/pull/19281.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/19281/head:pull/19281 PR: https://git.openjdk.org/jdk/pull/19281

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RFR: 8336881: [Linux] Support for hierarchical limits for Metrics
by Severin Gehwolf 23 Jan '26

23 Jan '26

Please review this fix for cgroups-based metrics reporting in the `jdk.internal.platform` package. This fix is supposed to address wrong reporting of certain limits if the limits aren't set at the leaf nodes. For example, on cg v2, the memory limit interface file is `memory.max`. Consider a cgroup path of `/a/b/c/d`. The current code only reports the limits (via Metrics) correctly if it's set at `/a/b/c/d/memory.max`. However, some systems - like a systemd slice - sets those limits further up the hierarchy. For example at `/a/b/c/memory.max`. `/a/b/c/d/memory.max` might be set to the value `max` (for unlimited), yet `/a/b/c/memory.max` would report the actual limit value (e.g. `1048576000`). This patch addresses this issue by: 1. Refactoring the interface lookup code to relevant controllers for cpu/memory. The CgroupSubsystem classes then delegate to those for the lookup. This facilitates having an API for the lookup of an updated limit in step 2. 2. Walking the full hierarchy of the cgroup path (if any), looking for a lower limit than at the leaf. Note that it's not possible to raise the limit set at a path closer to the root via the interface file at a further-to-the-leaf-level. The odd case out seems to be `max` values on some systems (which seems to be the default value). As an optimization this hierarchy walk is skipped on containerized systems (like K8S), where the limits are set in interface files at the leaf nodes of the hierarchy. Therefore there should be no change on those systems. This patch depends on the Hotspot change implementing the same for the JVM so that `Metrics.isContainerized()` works correctly on affected systems where `-XshowSettings:system` currently reports `System not containerized` due to the missing JVM fix. A test framework for such hierarchical systems has been proposed in [JDK-8333446](https://bugs.openjdk.org/browse/JDK-8333446). This patch adds a test using that framework among some simpler unit tests. Thoughts? Testing: - [ ] GHA - [x] Container tests on Linux x86_64 on cg v1 and cg v2 systems - [x] Some manual testing using systemd slices ------------- Depends on: https://git.openjdk.org/jdk/pull/17198 Commit messages: - 8336881: [Linux] Support for hierarchical limits for Metrics Changes: https://git.openjdk.org/jdk/pull/20280/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20280&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8336881 Stats: 1511 lines in 24 files changed: 1260 ins; 152 del; 99 mod Patch: https://git.openjdk.org/jdk/pull/20280.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/20280/head:pull/20280 PR: https://git.openjdk.org/jdk/pull/20280

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RFR: 8315585: Optimization for decimal to string
by Shaojin Wen 23 Jan '26

23 Jan '26

Continue to complete PR #16006 and PR #21593 to improve BigDecimal::toString and BigDecimal::toPlainString performance and reduce duplicate code ------------- Commit messages: - simplify and comments - simplify - simplify - code style - revert change - bug fix - bug fix - refactor - Revert "simplify scale2" - simplify scale2 - ... and 15 more: https://git.openjdk.org/jdk/compare/f446cefe...cb88e0ef Changes: https://git.openjdk.org/jdk/pull/23310/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23310&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8315585 Stats: 448 lines in 3 files changed: 237 ins; 118 del; 93 mod Patch: https://git.openjdk.org/jdk/pull/23310.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/23310/head:pull/23310 PR: https://git.openjdk.org/jdk/pull/23310

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RFR: 8328821: Map.of().entrySet() mutators should throw UnsupportedOperationException
by Liam Miller-Cushon 27 Nov '25

27 Nov '25

This change overrides mutator methods in the implementation returned by `Map.of().entrySet()` to throw `UnsupportedOperationException`. ------------- Commit messages: - Use AbstractImmutableSet - Throw UOE for all Map.of().entrySet() mutator methods - 8328821: Make the ImmutableCollections clear() call consistent Changes: https://git.openjdk.org/jdk/pull/18522/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18522&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8328821 Stats: 36 lines in 2 files changed: 35 ins; 0 del; 1 mod Patch: https://git.openjdk.org/jdk/pull/18522.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/18522/head:pull/18522 PR: https://git.openjdk.org/jdk/pull/18522

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RFR: 8173970: jar tool should have a way to extract to a directory
by Jaikiran Pai 13 Nov '25

13 Nov '25

Can I please get a review for this patch which proposes to implement the enhancement request noted in https://bugs.openjdk.java.net/browse/JDK-8173970? The commit in this PR introduces the `-o` and `--output-dir` option to the `jar` command. The option takes a path to a destination directory as a value and extracts the contents of the jar into that directory. This is an optional option and the changes in the commit continue to maintain backward compatibility where the jar is extracted into current directory, if no `-o` or `--output-dir` option has been specified. As far as I know, there hasn't been any discussion on what the name of this new option should be. I was initially thinking of using `-d` but that is currently used by the `jar` command for a different purpose. So I decided to use `-o` and `--output-dir`. This is of course open for change depending on any suggestions in this PR. The commit in this PR also updates the `jar.properties` file which contains the English version of the jar command's `--help` output. However, no changes have been done to the internationalization files corresponding to this one (for example: `jar_de.properties`), because I don't know what process needs to be followed to have those files updated (if at all they need to be updated). The commit also includes a jtreg testcase which verifies the usage of this new option. ------------- Commit messages: - 8173970: jar tool should have a way to extract to a directory Changes: https://git.openjdk.java.net/jdk/pull/2752/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2752&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8173970 Stats: 268 lines in 4 files changed: 262 ins; 0 del; 6 mod Patch: https://git.openjdk.java.net/jdk/pull/2752.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/2752/head:pull/2752 PR: https://git.openjdk.java.net/jdk/pull/2752

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RFR: 8346719: Add relaunchers to the static JDK image for missing executables
by Magnus Ihse Bursie 05 Nov '25

05 Nov '25

In the static JDK image, a single humongous java executable is generated, and no other launcher, such as javac. This makes it impossible to run our jtreg tests, which assume these are present. The solution is fortunately simply: we just need to add a bunch of trivial launchers, which are thin wrappers that execute the main java binary, with the proper arguments. This will result in the same behavior as the normal dynamic launchers, only that we will need to take the detour of launching another process instead of calling directly into the JLI library. ------------- Commit messages: - Revert "8352766: Problemlist hotspot tier1 tests requiring tools that are not included in static JDK" - Add build and main launcher support for relaunchers - Add native relaunchers - Simplify and prepare the main.c launcher Changes: https://git.openjdk.org/jdk/pull/24380/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24380&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8346719 Stats: 659 lines in 9 files changed: 518 ins; 111 del; 30 mod Patch: https://git.openjdk.org/jdk/pull/24380.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/24380/head:pull/24380 PR: https://git.openjdk.org/jdk/pull/24380

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RFR: 8355223: Improve documentation on @IntrinsicCandidate
by Chen Liang 22 Oct '25

22 Oct '25

In offline discussion, we noted that the documentation on this annotation does not recommend minimizing the intrinsified section and moving whatever can be done in Java to Java; thus I prepared this documentation update, to shrink a "TLDR" essay to something concise for readers, such as pointing to that list at `vmIntrinsics.hpp` instead of "a list". ------------- Commit messages: - 8355223: Improve documentation on @IntrinsicCandidate Changes: https://git.openjdk.org/jdk/pull/24777/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24777&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8355223 Stats: 91 lines in 1 file changed: 4 ins; 65 del; 22 mod Patch: https://git.openjdk.org/jdk/pull/24777.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/24777/head:pull/24777 PR: https://git.openjdk.org/jdk/pull/24777

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