June 2024 - core-libs-dev

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Core reflection's generic signature parsing uses an ancient library with outdated visitor pattern on a tree model and contains unnecessary boilerplates.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: 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: 8306055: Add a built-in Catalog to JDK XML module
by Joe Wang 16 Oct '25

16 Oct '25

Implement the built-in Catalog. ------------- Commit messages: - fix whitespace error - 8306055: Add a built-in Catalog to JDK XML module Changes: https://git.openjdk.org/jdk/pull/16719/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16719&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8306055 Stats: 1641 lines in 50 files changed: 1429 ins; 118 del; 94 mod Patch: https://git.openjdk.org/jdk/pull/16719.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/16719/head:pull/16719 PR: https://git.openjdk.org/jdk/pull/16719

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RFR: JDK-8266431: Dual-Pivot Quicksort improvements (Radix sort)
by Laurent Bourgès 21 Sep '25

21 Sep '25

* Optimized mixed insertion sort * Optimized insertion sort * Optimized Radix sort * Updated microbenchmark I am going on previous PR by Vladimir Yaroslavskyi: https://github.com/openjdk/jdk/pull/3938 ------------- Commit messages: - JDK-8266431: Dual-Pivot Quicksort improvements (Radix sort) Changes: https://git.openjdk.org/jdk/pull/13568/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13568&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8266431 Stats: 4022 lines in 4 files changed: 1747 ins; 1272 del; 1003 mod Patch: https://git.openjdk.org/jdk/pull/13568.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/13568/head:pull/13568 PR: https://git.openjdk.org/jdk/pull/13568

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RFR: 8320759: Creation of random BigIntegers can be made faster
by fabioromano1 02 Jul '25

02 Jul '25

A faster and simpler way to generate random BigIntegers, avoiding eventually trimming of leading zeros in magnitude array. ------------- Commit messages: - Optimized randomBits(int, Random) - Removed trailing whitespaces - Correct randomBits(int, Random) - Update BigInteger.java - Merge branch 'openjdk:master' into patch-4 - Merge branch 'patch-4' of https://github.com/fabioromano1/jdk into patch-4 - Merge branch 'openjdk:master' into patch-4 - An optimization - Correct BigInteger(int , Random) - Made random generation of BigIntegers faster Changes: https://git.openjdk.org/jdk/pull/16817/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16817&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8320759 Stats: 39 lines in 1 file changed: 16 ins; 8 del; 15 mod Patch: https://git.openjdk.org/jdk/pull/16817.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/16817/head:pull/16817 PR: https://git.openjdk.org/jdk/pull/16817

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RFR: 8282429: StringBuilder/StringBuffer.toString() skip compressing for UTF16 strings
by Xin Liu 29 May '25

29 May '25

If AbstractStringBuilder only grow, the inflated value which is encoded in UTF16 can't be compressed. toString() can skip compression in this case. This can save an ArrayAllocation in StringUTF16::compress. java.io.BufferedRead::readLine() is a case that StringBuilder grows only. ------------- Commit messages: - Add a microbenchmark. - 8282429: StringBuilder/StringBuffer.toString() skip compressing for UTF16 strings Changes: https://git.openjdk.java.net/jdk/pull/7671/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7671&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8282429 Stats: 44 lines in 5 files changed: 37 ins; 3 del; 4 mod Patch: https://git.openjdk.java.net/jdk/pull/7671.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/7671/head:pull/7671 PR: https://git.openjdk.java.net/jdk/pull/7671

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Re: RFR: 8266013: Unexpected replacement character handling on stateful CharsetEncoder [v2]
by Ichiroh Takiguchi 27 May '25

27 May '25

> When an invalid character is converted by getBytes() method, the character is converted to replacement byte data. > Shift code (SO/SI) may not be added into right place by EBCDIC Mix charset. > EBCDIC Mix charset encoder is stateful encoder. > Shift code should be added by switching character set. > On x-IBM1364, "\u3000\uD800" should be converted to "\x0E\x40\x40\x0F\x6F", but "\x0E\x40\x40\x6F\x0F" > SI is not in right place. > > Also ISO2022 related charsets use escape sequence to switch character set. > But same kind of issue is there. Ichiroh Takiguchi has updated the pull request incrementally with one additional commit since the last revision: 8266013: Unexpected replacement character handling on stateful CharsetEncoder ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/3719/files - new: https://git.openjdk.java.net/jdk/pull/3719/files/d6a0a41b..33107e67 Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3719&range=01 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3719&range=00-01 Stats: 59 lines in 2 files changed: 40 ins; 5 del; 14 mod Patch: https://git.openjdk.java.net/jdk/pull/3719.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/3719/head:pull/3719 PR: https://git.openjdk.java.net/jdk/pull/3719

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RFR: 8294960: Convert java.base/java.lang.invoke package to use the Classfile API to generate lambdas and method handles
by Adam Sotona 16 May '25

16 May '25

java.base java.lang.invoke package heavily uses ASM to generate lambdas and method handles. This patch converts ASM calls to Classfile API. This PR is continuation of https://github.com/openjdk/jdk/pull/12945 Any comments and suggestions are welcome. Please review. Thank you, Adam ------------- Commit messages: - fixed InnerClassLambdaMetafactory for hidden caller classes - performance improvements - consolidation of descriptors handling - InvokerBytecodeGenerator::emit... improvements - 8294960: Convert java.base/java.lang.invoke package to use the Classfile API to generate lambdas and method handlers Changes: https://git.openjdk.org/jdk/pull/17108/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17108&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8294960 Stats: 2142 lines in 13 files changed: 443 ins; 859 del; 840 mod Patch: https://git.openjdk.org/jdk/pull/17108.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/17108/head:pull/17108 PR: https://git.openjdk.org/jdk/pull/17108

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RFR: 8268829: Provide an optimized way to walk the stack with Class object only
by Mandy Chung 02 May '25

02 May '25

8268829: Provide an optimized way to walk the stack with Class object only `StackWalker::walk` creates one `StackFrame` per frame and the current implementation allocates one `StackFrameInfo` and one `MemberName` objects per frame. Some frameworks like logging may only interest in the Class object but not the method name nor the BCI, for example, filters out its implementation classes to find the caller class. It's similar to `StackWalker::getCallerClass` but allows a predicate to filter out the element. This PR proposes to add `Option.NO_METHOD_INFO` new stack walking option. If no method information is needed, this option can be used such that the stack walker will save the overhead (1) to extract the method information and (2) the memory used for the stack walking. In addition, this can also fix - [8311500](https://bugs.openjdk.org/browse/JDK-8311500): StackWalker.getCallerClass() throws UOE if invoked reflectively Adding `NO_METHOD_TIME` option provides a simple way for existing code, for example logging frameworks, to take advantage of this enhancement with the least change as it can keep the existing implementation in traversing `StackFrame`s. For example: to find the first caller filtering a known list of implementation class, existing code can just add `NO_METHOD_INFO` in the call to `StackWalker::getInstance` to create a stack walker instance: StackWalker walker = StackWalker.getInstance(Option.RETAIN_CLASS_REFERENCE, NO_METHOD_INFO); Optional<Class<?>> callerClass = walker.walk(s -> s.map(StackFrame::getDeclaringClass) .filter(interestingClasses::contains) .findFirst()); If method information is accessed on the `StackFrame`s produced by this stack walker such as `StackFrame::getMethodName`, then `UnsupportedOperationException` will be thrown. The alternative considered is to provide a new API: `<T> T walkClass(Function<? super Stream<Class<?>, ? extends T> function)` In this case, the caller would need to pass a function that takes a stream of `Class` object instead of `StackFrame`. Existing code would have to modify calls to the `walk` method to `walkClass` and the function body. ### Implementation Details If `NO_METHOD_NAME` is set, the implementation creates `ClassFrameInfo[]` buffer that is filled by the VM during stack walking. `ClassFrameInfo` holds the Class instance plus `flags` which indicate if it's caller sensitive or hidden. With this change, `StackWalker::getCallerClass` can also use `ClassFrameInfo[]` buffer to replace the special `Class` buffer and remove the special check in the VM. JDK-8311500 can be fixed in Java. If `NO_METHOD_NAME` is not set, the implementation creates `StackFrameInfo[]` buffer. `StackFrameInfo` is a subclass of `ClassFrameInfo`. It keeps `ResolvedMethodName` and all other method information. ### Performance The memory usage of the data structure (shown by -XX:PrintFieldLayout): | Type | Instance size | | ---- | ------------ | | `ClassFrameInfo` | 24 bytes | | `StackFrameInfo` | 48 bytes | | `ResolvedMethodName` | 24 bytes | | `MemberName` | 48 bytes | | `StackFrameInfo` (old) | 32 bytes | The existing implementation allocates a total of 104 bytes for each frame (`StackFrameInfo` + `MemberName` + `ResolvedMethodName`). The new implementation, without `NO_METHOD_INFO` option, allocates a total of 72 bytes for each frame (`StackFrameInfo` + `ResolvedMethodName`) which saves 30% of the buffer memory. With `NO_METHOD_INFO`, 24 bytes is allocated for each frame (only `ClassFrameInfo` is needed). In addition, it saves the overhead in creating `ResolvedMethodName` object in the VM. The microbenchmark shows that the runtime performance of stack walking with method information is 15-31% faster than the old implementation. Using `NO_METHOD_INFO` option, it is about 21-43% faster compared to traversing the frames without `NO_METHOD_INFO` in the new implementation. #### `StackWalker::getCallerClass` `StackWalkBench::getCallerClass` shows about 30-60 ns degradation. The old implementation creates a `Class` array of size 8 whereas the new implementation which creates a `ClassFrameInfo` array of size 8 initialized with 6 `ClassFrameInfo` elements. The new implementation of `getCallerClass` adds 144 bytes more, which is insignificant. The benefit of this is to do the filtering in Java rather than doing in VM. `StackWalkBench::getCallerClass` includes the cost of setting up the call stack. There is no good way to write a JMH benchmark just to measure the performance of `getCallerClass`. If I measured `getCallerClass` with a standalone benchmark, it shows `getCallerClass` takes roughly about 8500-10000 ns range on my macos-aarch64 machine. The 30-60 ns degradation is negligible. ------------- Commit messages: - fix trailing whitespace - Merge branch 'master' of https://github.com/openjdk/jdk into stackwalker-class - Update LocalLongHelper.java - clean up - Merge branch 'master' of https://github.com/openjdk/jdk into stackwalker-class - Add StackWalker.Option.NO_METHOD_INFO - Merge branch 'master' of https://github.com/openjdk/jdk into stackwalker-class - Merge branch 'master' of https://github.com/openjdk/jdk into stackwalker-class - Merge branch 'master' of https://github.com/openjdk/jdk into stackwalker-class - Merge branch 'master' of https://github.com/openjdk/jdk into stackwalker-class - ... and 3 more: https://git.openjdk.org/jdk/compare/78f74bc8...e9e2b390 Changes: https://git.openjdk.org/jdk/pull/15370/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15370&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8268829 Stats: 1026 lines in 30 files changed: 628 ins; 178 del; 220 mod Patch: https://git.openjdk.org/jdk/pull/15370.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/15370/head:pull/15370 PR: https://git.openjdk.org/jdk/pull/15370

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