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Release notes for Red Hat build of OpenJDK 21.0.6

Red Hat build of OpenJDK 21

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Abstract

The Release notes for Red Hat build of OpenJDK 21.0.6 document provides an overview of new features in Red Hat build of OpenJDK 21 and a list of potential known issues and possible workarounds.

Preface
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Open Java Development Kit (OpenJDK) is a free and open source implementation of the Java Platform, Standard Edition (Java SE). The Red Hat build of OpenJDK is available in four versions: 8u, 11u, 17u, and 21u.

Packages for the Red Hat build of OpenJDK are made available on Red Hat Enterprise Linux and Microsoft Windows and shipped as a JDK and JRE in the Red Hat Ecosystem Catalog.

To report an error or to improve our documentation, log in to your Red Hat Jira account and submit an issue. If you do not have a Red Hat Jira account, then you will be prompted to create an account.

Procedure

  1. Click the following link to create a ticket.
  2. Enter a brief description of the issue in the Summary.
  3. Provide a detailed description of the issue or enhancement in the Description. Include a URL to where the issue occurs in the documentation.
  4. Clicking Create creates and routes the issue to the appropriate documentation team.

Making open source more inclusive
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Red Hat is committed to replacing problematic language in our code, documentation, and web properties. We are beginning with these four terms: master, slave, blacklist, and whitelist. Because of the enormity of this endeavor, these changes will be implemented gradually over several upcoming releases. For more details, see our CTO Chris Wright’s message.

Red Hat will support select major versions of Red Hat build of OpenJDK in its products. For consistency, these versions remain similar to Oracle JDK versions that are designated as long-term support (LTS).

A major version of Red Hat build of OpenJDK will be supported for a minimum of six years from the time that version is first introduced. For more information, see the OpenJDK Life Cycle and Support Policy.

Note

RHEL 6 reached the end of life in November 2020. Because of this, Red Hat build of OpenJDK is not supporting RHEL 6 as a supported configuration.

Chapter 2. Differences from upstream OpenJDK 21
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Red Hat build of OpenJDK in Red Hat Enterprise Linux contains a number of structural changes from the upstream distribution of OpenJDK. The Microsoft Windows version of Red Hat build of OpenJDK attempts to follow Red Hat Enterprise Linux updates as closely as possible.

The following list details the most notable Red Hat build of OpenJDK 21 changes:

  • FIPS support. Red Hat build of OpenJDK 21 automatically detects whether RHEL is in FIPS mode and automatically configures Red Hat build of OpenJDK 21 to operate in that mode. This change does not apply to Red Hat build of OpenJDK builds for Microsoft Windows.
  • Cryptographic policy support. Red Hat build of OpenJDK 21 obtains the list of enabled cryptographic algorithms and key size constraints from the RHEL system configuration. These configuration components are used by the Transport Layer Security (TLS) encryption protocol, the certificate path validation, and any signed JARs. You can set different security profiles to balance safety and compatibility. This change does not apply to Red Hat build of OpenJDK builds for Microsoft Windows.
  • The src.zip file includes the source for all of the JAR libraries shipped with Red Hat build of OpenJDK.
  • Red Hat build of OpenJDK on RHEL uses system-wide timezone data files as a source for timezone information.
  • Red Hat build of OpenJDK on RHEL uses system-wide CA certificates.
  • Red Hat build of OpenJDK on Microsoft Windows includes the latest available timezone data from RHEL.
  • Red Hat build of OpenJDK on Microsoft Windows uses the latest available CA certificates from RHEL.

Chapter 3. Red Hat build of OpenJDK features
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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 earlier Red Hat build of OpenJDK 21 releases.

Note

For all the other changes and security fixes, see OpenJDK 21.0.6 Released.

Red Hat build of OpenJDK enhancements

Red Hat build of OpenJDK 21 provides enhancements to features originally created in earlier releases of Red Hat build of OpenJDK.

Option for jar command to avoid overwriting files when extracting an archive

In earlier Red Hat build of OpenJDK releases, when the jar tool extracted files from an archive, the jar tool overwrote any existing files with the same name in the target directory.

Red Hat build of OpenJDK 21.0.6 adds a new ‑k (or ‑‑keep-old-files) option that you can use to ensure that the jar tool does not overwrite existing files. You can specify this new option in either short or long format.

For example:

  • jar xkf myfile.jar
  • jar --extract ‑‑keep-old-files ‑‑file myfile.jar
Note

In Red Hat build of OpenJDK 21.0.6, the jar tool retains the old behavior by default. If you do not explicitly specify the ‑k (or ‑‑keep-old-files) option, the jar tool automatically overwrites any existing files with the same name.

See JDK-8335912 (JDK Bug System) and JDK bug system reference ID: JDK-8337499.

IANA time zone database updated to version 2024b

In Red Hat build of OpenJDK 21.0.6, the in-tree copy of the Internet Assigned Numbers Authority (IANA) time zone database is updated to version 2024b. This update is primarily concerned with improving historical data for Mexico, Mongolia, and Portugal.

This update to the IANA database also includes the following changes:

  • Asia/Choibalsan is an alias for Asia/Ulaanbaatar.
  • The Middle European Time (MET) time zone is equal to Central European Time (CET).

  • Some legacy time-zone IDs are mapped to geographical names rather than fixed offsets:

    • Eastern Standard Time (EST) is mapped to America/Panama rather than -5:00.
    • Mountain Standard Time (MST) is mapped to America/Phoenix rather than -7:00.
    • Hawaii Standard Time (HST) is mapped to Pacific/Honolulu rather than -10:00.

    Red Hat build of OpenJDK overrides the change in the legacy time-zone ID mappings by retaining the existing fixed-offset mapping.

See JDK-8339637 (JDK Bug System).

Chapter 4. Advisories related to this release
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The following advisories are issued to document bug fixes and CVE fixes included in this release:

Revised on 2025-01-30 11:26:19 UTC

Legal Notice
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The text of and illustrations in this document are licensed by Red Hat under a Creative Commons Attribution–Share Alike 3.0 Unported license ("CC-BY-SA"). An explanation of CC-BY-SA is available at http://creativecommons.org/licenses/by-sa/3.0/. In accordance with CC-BY-SA, if you distribute this document or an adaptation of it, you must provide the URL for the original version.
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