Chapter 3. OpenJDK features

Review the following release notes to understand new features and feature enhancements that have been included with the Red Hat build of OpenJDK 17.0.2 release:

IANA Time Zone Database

The Internet Assigned Numbers Authority (IANA) updated its Time Zone Database to version 2021c. Red Hat OpenJDK date and time libraries depends on IANA’s Time Zone Database for determining local time for various regions around the world.

For more information about IANA’s 2021c Time Zone Database release, see JDK-8274857.

For more information about IANA’s Time Zone Database, see Time Zone Database on the IANA website.

Red Hat build of OpenJDK 17 provides enhancements to features originally created in previous releases of Red Hat build of OpenJDK.

OpenJDK’s identification of Microsoft Windows versions

Before the Red Hat build of OpenJDK 17 release, the os.name system property that is retrieved from System.getProperty() and the HotSpot error logs would report Windows 10.0 on Microsoft Windows 11 and Windows Server 2019 on Microsoft Windows Server 2022. Red Hat build of OpenJDK now identifies the correct version on these systems.

System property behavior change

Red Hat build of OpenJDK 17 reverts the behavior of the file.encoding system property to a state identical to Red Hat build of OpenJDK 11 on most supported platforms, except for macOS. This change improves how the system property behaves on the Microsoft Windows platform, where the system locales and user locales differ.

For more information about the behavior change to the file.encoding system property, see JDK-8275343.

Vector class update

Red Hat build of OpenJDK 17 updates the java.util.Vector class, so that this class now reports any ClassNotFoundException messages that have been generated with the java.io.ObjectInputStream.GetField.get(name, object) method during the deserialization process. These exception messages occur when a vector’s class, wrapped inside an element, is not found.

Before the java.util.Vector class update, the class reported any StreamCorruptedException messages when the previously detailed incident occurred. A StreamCorruptedException message does not provide information about a missing class.

For more information about the update to the java.util.Vector class, see JDK-8277157.

Z Garbage Collector bug fix

Before the Red Hat build of OpenJDK 17 update, the Z Garbage Collector (ZGC) experienced lengthy Concurrent Process Non-strong References times that caused latency and throughput issues for Java applications that use ZGC for memory management. You could determine these lengthy times by entering the -Xlog:gc* against a garbage collector (GC) log in your command-line interface.

The Red Hat build of OpenJDK 17 release removes the bug that caused these issues, so the ZGC can now achieve shorter Concurrent Process Non-strong References times.

For more information about ZGC bug fix, see JDK-8277533.

Review the following release notes to understand pre-existing features that have been either deprecated or removed in the Red Hat build of OpenJDK 17.0.2 release:

Google GlobalSign root certificate

Red Hat build of OpenJDK 17.0.2 removes the following root certificate from the cacerts keystore:

For more information about this removed Google GlobalSign root certificate, see JDK-8272535.