RELEASE NOTES: JDK 21.0.13

Notes generated: Wed Aug 12 07:04:39 CEST 2026

JEPs

None.

RELEASE NOTES

hotspot/compiler

Issue Description
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-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

Issue Description
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.
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.

FIXED ISSUES

client-libs/2d

Priority Bug Summary
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

Priority Bug Summary
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

Priority Bug Summary
P3 JDK-8372757 MacOS, Accessibility: Crash in [MenuAccessibility accessibilityChildren] after JDK-8341311

client-libs/javax.sound

Priority Bug Summary
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

Priority Bug Summary
P4 JDK-8382063 Jtreg test javax/swing/SwingWorker/TestDoneBeforeDoInBackground.java fails

core-libs

Priority Bug Summary
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

Priority Bug Summary
P4 JDK-8389492 [21u] java/io/Serializable/records/ProhibitedMethods.java fails after JDK-8307843 backport in othervm mode

core-libs/java.lang

Priority Bug Summary
P4 JDK-8352565 Add native method implementation of Reference.get()

core-libs/java.nio

Priority Bug Summary
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

Priority Bug Summary
P4 JDK-8341625 Improve ZipFile validation of the END header

core-libs/java.util:i18n

Priority Bug Summary
P4 JDK-8380993 [REDO] Incorrect Interpretation of POSIX TZ Environment Variable on AIX

core-svc/javax.management

Priority Bug Summary
P4 JDK-8384804 JMX remote bootstrap tests fail on Windows

hotspot/compiler

Priority Bug Summary
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-8341527 AVX-512 intrinsic for SHA3
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

Priority Bug Summary
P4 JDK-8385454 Provide more NUMA related information in hsinfo/hserr files

hotspot/jfr

Priority Bug Summary
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

Priority Bug Summary
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

Priority Bug Summary
P4 JDK-8387625 Add "dt_socket" to `CheckedFeatures.notImplemented` for Windows/ARM64

infrastructure

Priority Bug Summary
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

Priority Bug Summary
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

security-libs/java.security

Priority Bug Summary
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-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

Priority Bug Summary
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

tools

Priority Bug Summary
P4 JDK-8387985 sun/tools/jstat shell tests fail on platforms that do not support ParallelGC