Chapter 3. Red Hat build of OpenJDK features The latest Red Hat build of OpenJDK 21 release might include new features. Additionally, the latest release might enhance, deprecate, or remove features that originated from Red Hat build of OpenJDK 21 releases. Note For all the other changes and security fixes, see Red Hat build of OpenJDK 21.0.2 Released . Red Hat build of OpenJDK enhancements Red Hat build of OpenJDK 21 provides enhancements to features originally created in releases of Red Hat build of OpenJDK. KEEPALIVE extended socket options support added on Windows On Windows 10 version 1709 or later platforms, the java.net.ExtendedSocketOptions class now supports the TCP_KEEPIDLE and TCP_KEEPINTERVAL options. Similarly, on Windows 10 version 1703 or later platforms, the java.net.ExtendedSocketOptions class now supports the TCP_KEEPCOUNT option. See JDK-8308593 (JDK Bug System) . Fixed potential JVM failures when using ZGC and a non-default ObjectAlignmentInBytes value In the initial release of Red Hat build of OpenJDK 21, if you ran the JVM with the -XX:+UseZGC option and a non-default value for -XX:ObjectAlignmentInBytes , the JVM could fail or malfunction. Red Hat build of OpenJDK 21.0.2 resolves this issue to ensure that you can successfully use the Z Garbage Collector (ZGC) and non-default values for Java object alignment when running the JVM. See JDK-8315082 (JDK Bug System) . Peak values for committed memory included in NMT reports In Red Hat build of OpenJDK 21.0.2, Native Memory Tracking (NMT) reports now show the peak value for all categories. The peak value is the highest value for committed memory in a given NMT category over the lifetime of the JVM process. If the committed memory for a category is currently at its highest value, the NMT report shows an at peak value; otherwise, the NMT report shows the historic peak value. For example, the following report output shows that compiler arena memory peaked above 6 MB but is now approximately 200KB: See JDK-8317772 (JDK Bug System) . JVM warnings about unsupported THPs on Red Hat Enterprise Linux On Red Hat Enterprise Linux platforms, if Transparent Huge Pages (THPs) are requested but not supported, the JVM now prints the following message to standard output: See JDK-8313782 (JDK Bug System) . Let's Encrypt ISRG Root X2 CA certificate added In Red Hat build of OpenJDK 21.0.2, the cacerts truststore includes the Internet Security Research Group (ISRG) Root X2 certificate authority (CA) certificate from Let's Encrypt: Name: Let's Encrypt Alias name: letsencryptisrgx2 Distinguished name: CN=ISRG Root X2, O=Internet Security Research Group, C=US See JDK-8317374 (JDK Bug System) . Digicert, Inc. root certificates added In Red Hat build of OpenJDK 21.0.2, the cacerts truststore includes four Digicert, Inc. root certificates: Certificate 1 Name: DigiCert, Inc. Alias name: digicertcseccrootg5 Distinguished name: CN=DigiCert CS ECC P384 Root G5, O="DigiCert, Inc.", C=US Certificate 2 Name: DigiCert, Inc. Alias name: digicertcsrsarootg5 Distinguished name: CN=DigiCert CS RSA4096 Root G5, O="DigiCert, Inc.", C=US Certificate 3 Name: DigiCert, Inc. Alias name: digicerttlseccrootg5 Distinguished name: CN=DigiCert TLS ECC P384 Root G5, O="DigiCert, Inc.", C=US Certificate 4 Name: DigiCert, Inc. Alias name: digicerttlsrsarootg5 Distinguished name: CN=DigiCert TLS RSA4096 Root G5, O="DigiCert, Inc.", C=US See JDK-8318759 (JDK Bug System) . eMudhra Technologies Limited root certificates added In Red Hat build of OpenJDK 21.0.2, the cacerts truststore includes three eMudhra Technologies Limited root certificates: Certificate 1 Name: eMudhra Technologies Limited Alias name: emsignrootcag1 Distinguished name: CN=emSign Root CA - G1, O=eMudhra Technologies Limited, OU=emSign PKI, C=IN Certificate 2 Name: eMudhra Technologies Limited Alias name: emsigneccrootcag3 Distinguished name: CN=emSign ECC Root CA - G3, O=eMudhra Technologies Limited, OU=emSign PKI, C=IN Certificate 3 Name: eMudhra Technologies Limited Alias name: emsignrootcag2 Distinguished name: CN=emSign Root CA - G2, O=eMudhra Technologies Limited, OU=emSign PKI, C=IN See JDK-8319187 (JDK Bug System) . Telia Root CA v2 certificate added In Red Hat build of OpenJDK 21.0.2, the cacerts truststore includes the Telia Root CA v2 certificate: Name: Telia Root CA v2 Alias name: teliarootcav2 Distinguished name: CN=Telia Root CA v2, O=Telia Finland Oyj, C=FI See JDK-8317373 (JDK Bug System) .

Commands:
Compiler (arena=196KB #4) (peak=6126KB #16)
UseTransparentHugePages disabled; transparent huge pages are not supported by the operating system.