RELEASE NOTES FOR: 21.0.13
====================================================================================================

Notes generated: Fri Aug 14 05:30:36 CEST 2026

Hint: Prefix bug IDs with https://bugs.openjdk.org/browse/ to reach the relevant JIRA entry.

JAVA ENHANCEMENT PROPOSALS (JEP):

  None.

RELEASE NOTES:

hotspot/compiler:

    JDK-8348561: ML-DSA Performance Improved

      The performance of the ML-DSA key generation, sign, and verify operations has been improved
      significantly, 1.5 - 2.5 times depending on operation type and input, on the aarch64 and
      AVX-512 platforms.

    JDK-8349721: ML-KEM Performance Improved

      The performance of the ML-KEM key generation, encapsulation, and decapsulation operations has
      been improved significantly, 1.9 - 2.7 times depending on operation type and platform, on the
      aarch64 and AVX-512 platforms.

    JDK-8351412: ML-KEM Performance Improved

      The performance of the ML-KEM key generation, encapsulation, and decapsulation operations has
      been improved significantly, 1.9 - 2.7 times depending on operation type and platform, on the
      aarch64 and AVX-512 platforms.

    JDK-8351034: ML-DSA Performance Improved

      The performance of the ML-DSA key generation, sign, and verify operations has been improved
      significantly, 1.5 - 2.5 times depending on operation type and input, on the aarch64 and
      AVX-512 platforms.

    JDK-8341527: SHA3 Performance Improved

      The performance of the `MessageDigest` implementations that belong to the SHA3 family
      (SHA3-224, SHA3-256, SHA3-384, and SHA3-512) has been improved by 6-27%, depending on digested
      message length and on the platform used. An additional 30-40% can be experienced on AVX-512
      capable platforms due to new intrinsic implementations on that platform.

security-libs/java.security:

    JDK-8354305: SHAKE128-256 and SHAKE256-512 as MessageDigest Algorithms

      Two new `MessageDigest` algorithms, SHAKE128-256 and SHAKE256-512, have been added to the SUN
      provider. These are fixed-length versions of the SHAKE128 and SHAKE256 Extendable-Output
      Functions (XOFs) defined in NIST FIPS 202. For more information, see [The SUN
      Provider](https://docs.oracle.com/en/java/javase/25/security/oracle-providers.html#GUID-3A80CC46-91E1-4E47-AC51-CB7B782CEA7D).

    JDK-8333867: SHA3 Performance Improved

      The performance of the `MessageDigest` implementations that belong to the SHA3 family
      (SHA3-224, SHA3-256, SHA3-384, and SHA3-512) has been improved by 6-27%, depending on digested
      message length and on the platform used. An additional 30-40% can be experienced on AVX-512
      capable platforms due to new intrinsic implementations on that platform.


ALL FIXED ISSUES, BY COMPONENT AND PRIORITY:

client-libs/2d:
  (P3) JDK-8378506: [macOS] Window content not updated when rendering to multiple windows
  (P3) JDK-8387593: Using XOR mode to clear the content leaves some traces in metal
  (P4) JDK-8365426: [macos26] Graphics2D tests fail on new macOS 26

client-libs/java.awt:
  (P4) JDK-8343739: Test java/awt/event/KeyEvent/ExtendedKeyCode/ExtendedKeyCodeTest.java failed: Wrong extended key code
  (P4) JDK-8372546: UnixMultiResolutionSplashTest.java fails intermittently on Ubuntu_24.04

client-libs/javax.accessibility:
  (P3) JDK-8372757: MacOS, Accessibility: Crash in [MenuAccessibility accessibilityChildren] after JDK-8341311

client-libs/javax.sound:
  (P3) JDK-7067310: 3 tests from closed/javax/sound/sampled caused BSOD on win 7 x86
  (P4) JDK-8307574: ClipIsRunningAfterStop.java failed with "../nptl/pthread_mutex_lock.c:81: __pthread_mutex_lock: Assertion `mutex->__data.__owner == 0' failed."
  (P4) JDK-8308395: javax/sound/sampled/Clip/ClipFlushCrash.java timed out

client-libs/javax.swing:
  (P4) JDK-8382063: Jtreg test javax/swing/SwingWorker/TestDoneBeforeDoInBackground.java fails

core-libs:
  (P3) JDK-8378180: Compiling OpenJDK with C23 C-Compiler gives warning: initialization discards ‘const’ qualifier from pointer target type
  (P4) JDK-8388431: [21u] Backport of JDK-8352565 misses previous vm symbol to be deleted

core-libs/java.io:serialization:
  (P4) JDK-8389492: [21u] java/io/Serializable/records/ProhibitedMethods.java fails after JDK-8307843 backport in othervm mode

core-libs/java.lang:
  (P4) JDK-8352565: Add native method implementation of Reference.get()

core-libs/java.nio:
  (P4) JDK-8375294: (fs) Files.copy can fail with EOPNOTSUPP when copy_file_range not supported
  (P4) JDK-8384163: (so) SocketChannel.connect and finishConnect() exception messages could be improved

core-libs/java.util.jar:
  (P4) JDK-8341625: Improve ZipFile validation of the END header

core-libs/java.util:i18n:
  (P4) JDK-8380993: [REDO] Incorrect Interpretation of POSIX TZ Environment Variable on AIX

core-svc/javax.management:
  (P4) JDK-8384804: JMX remote bootstrap tests fail on Windows

hotspot/compiler:
  (P3) JDK-8348561: Add aarch64 intrinsics for ML-DSA
  (P3) JDK-8349721: Add aarch64 intrinsics for ML-KEM
  (P3) JDK-8351034: Add AVX-512 intrinsics for ML-DSA
  (P3) JDK-8351412: Add AVX-512 intrinsics for ML-KEM
  (P3) JDK-8341527: AVX-512 intrinsic for SHA3
  (P3) JDK-8354926: Remove remnants of debugging in the fix for JDK-8348561 and JDK-8349721
  (P4) JDK-8386578: double_keccak stub does not set its return value on x86
  (P4) JDK-8310331: JitTester: Exclude java.lang.Math.random
  (P4) JDK-8369020: Test compiler/intrinsics/TestLongUnsignedDivMod.java completed and timed out

hotspot/gc:
  (P4) JDK-8385454: Provide more NUMA related information in hsinfo/hserr files

hotspot/jfr:
  (P4) JDK-8365498: jdk/jfr/event/os/TestCPULoad.java fails with Expected at least one event
  (P4) JDK-8386345: Remove redundant @requires from TestGarbageCollectionEventWithZMinor

hotspot/runtime:
  (P3) JDK-8377991: TestLimitsUpdating.java fails with runtime exception even after JDK-8370492 is fixed
  (P4) JDK-8383611: assert(count == os::processor_count() + 1) failed: invalid enumeration!
  (P4) JDK-8375125: assert(false) failed: "Attempting to acquire lock NativeHeapTrimmer_lock/nosafepoint out of order with lock ConcurrentHashTableResize_lock/nosafepoint-2 -- possible deadlock" when using native heap trimmer
  (P4) JDK-8374343: Fix SIGSEGV when lib/modules is unreadable
  (P4) JDK-8334502: gtest/GTestWrapper.java fails on armhf due to LogDecorations.iso8601_utctime_test
  (P4) JDK-8364106: Include java.runtime.version in thread dump output
  (P4) JDK-8343698: Linux x86_64 lto build gives a lot of warnings and fails lto-wrapper: fatal error: make returned 2 exit status
  (P4) JDK-8372615: Many container tests fail when running rootless on cgroup v1

hotspot/svc:
  (P4) JDK-8387625: Add "dt_socket" to `CheckedFeatures.notImplemented` for Windows/ARM64

infrastructure:
  (P3) JDK-8361950: Update to use jtreg 8
  (P3) JDK-8369488: Update to use jtreg 8.1
  (P3) JDK-8376355: Update to use jtreg 8.2.1
  (P4) JDK-8385508: Bump update version for OpenJDK: jdk-21.0.13

infrastructure/build:
  (P4) JDK-8371893: [macOS] use dead_strip linker option to reduce binary size
  (P4) JDK-8306281: function isWsl() returns false on WSL2
  (P4) JDK-8247690: RunTest does not support running of JTREG manual tests

performance/libraries:
  (P4) JDK-8353478: Update crypto microbenchmarks to cover ML-DSA, ML-KEM, and HSS algorithms

security-libs/java.security:
  (P2) JDK-8345057: ML_KEM NamedParameterSpec constants removed by ML-DSA integration
  (P2) JDK-8342002: sun/security/tools/keytool/GenKeyPairSigner.java failed due to missing certificate output
  (P2) JDK-8356051: Update SignatureUtil.java with the new KnownOIDs
  (P3) JDK-8340327: A common framework to support public key algorithms with standard parameter sets
  (P3) JDK-8374886: CAInterop.java#microsoftrsa2017 test fails as EE certificate does not specify OCSP responder
  (P3) JDK-8298387: Implement JEP 497: Quantum-Resistant Module-Lattice-Based Digital Signature Algorithm
  (P3) JDK-8338587: Internal XOF Methods for SHAKE128 and SHAKE256
  (P3) JDK-8354305: SHAKE128 and SHAKE256 MessageDigest algorithms
  (P3) JDK-8345533: Switch ML-DSA implementation to FIPS 204 final
  (P3) JDK-8349017: Update ML tests to verify against ACVP 1.1.0.38 version
  (P4) JDK-8381771: Add a check for DNS label not to end with a hyphen
  (P4) JDK-8385584: CAInterop.java#buypassclass3ca fails with Intermediate Root CA not found in the chain
  (P4) JDK-8381937: Make exceptions in Java_sun_security_mscapi_CKeyPairGenerator generateCKeyPair more specific
  (P4) JDK-8347606: Optimize Java implementation of ML-DSA 
  (P4) JDK-8345512: Remove wrapper functions for intrinsics in PQC algorithms
  (P4) JDK-8333867: SHA3 performance can be improved
  (P4) JDK-8342442: Static ACVP sample tests

security-libs/javax.crypto:
  (P3) JDK-8298390: Implement JEP 496: Quantum-Resistant Module-Lattice-Based Key Encapsulation Mechanism
  (P4) JDK-8350589: Investigate cleaner implementation of AArch64 ML-DSA intrinsic introduced in JDK-8348561
  (P4) JDK-8347608: Optimize Java implementation of ML-KEM

security-libs/javax.net.ssl:
  (P4) JDK-8361125: Fix typo in onTradAbsence

tools:
  (P4) JDK-8387985: sun/tools/jstat shell tests fail on platforms that do not support ParallelGC