Chapter 3. Red Hat build of OpenJDK features

The latest Red Hat build of OpenJDK 17 release might include new features. Additionally, the latest release might enhance, deprecate, or remove features that originated from previous Red Hat build of OpenJDK 17 releases.

Red Hat build of OpenJDK enhancements

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

Enhanced BMP bounds

By default, Red Hat build of OpenJDK 17.0.6 disables loading a linked International Color Consortium (ICC) profile in a BMP image. You can enable this functionality by setting the new sun.imageio.bmp.enabledLinkedProfiles property to true. This property replaces the old sun.imageio.plugins.bmp.disableLinkedProfiles property

See JDK-8295687 (JDK Bug System).

Improved banking of sounds

Previously, the SoundbankReader implementation, com.sun.media.sound.JARSoundbankReader, downloaded a JAR soundbank from a URL. For Red Hat build of OpenJDK 17.0.6, this behavior is now disabled by default. To re-enable the behavior, set the new system property jdk.sound.jarsoundbank to true.

See JDK-8293742 (JDK Bug System).

Enhanced Datagram Transport Layer Security (DTLS) performance

Red Hat build of OpenJDK now exchanges DTLS cookies for all new and resumed handshake communications.

To re-enable the previous release behavior, set the new system property jdk.tls.enableDtlsResumeCookie to false.

See JDK-8287411 (JDK Bug System).

Added note for LoginModule implementation

The Red Hat build of OpenJDK 9 release changed the Set implementation, which holds principals and credentials, so that the implementation can reject null values. Any attempts to call add(null), contains(null), or remove(null) would throw a NullPointerException message.

The Red Hat build of OpenJDK 9 release did not update the logout() method in the LoginModule implementation to check for null values. These values could occur because of a failed login attempt, which can cause a logout() call to throw a NullPointerException message.

The Red Hat build of OpenJDK 17.0.6 release updates the LoginModule implementations to check for null values. Additionally, the release adds an implementation note to the specification that states the change also applies to third-party modules. The note advises developers of third-party modules to verify that a logout() method does not throw a NullPointerException message.