The Liberty-for-Java Buildpack v3.43 now includes Liberty Runtime 20.0.0.4.

This buildpack contains two production versions of Liberty—a default version that remains constant for approximately three months and the latest version as an alternate. In this new buildpack, the default version is 20.0.0.3 and the alternate version is 20.0.0.4. To use the alternate version of Liberty follow these instructions.

An existing application will not be affected by the new buildpack until you redeploy or restage it. After redeployment, existing applications should continue to run “as is” without any additional changes. New applications will automatically use the new buildpack.

Liberty 20.0.0.4 provides support for MicroProfile 3.3. To use MicroProfile 3.3, you will need use the alternate Liberty runtime following these instructions and specify the features javaee-8.0 and microProfile-3.3 in the manifest.yml, an environment variable, or in the server.xml.   

To set using the JBP_CONFIG_LIBERTY environment variable, use the Cloud Foundry set-env command:

cf set-env GetStartedJava JBP_CONFIG_LIBERTY '[version: +, app_archive: {features: [javaee-8.0,microProfile-3.3]}]'

To set using the manifest.yml, add the following: 

env:
   IBM_LIBERTY_MONTHLY: true
   JBP_CONFIG_LIBERTY: '[version: +, app_archive: {features: [javaee-8.0,microProfile-3.3]}]'

Verbose GC logging in the IBM JRE is now enabled by default. The logs are stored in /home/vcap/logs. 
Verbose GC logging gives insight into the actions that the Garbage Collector is taking. This allows an application to be monitored and better tuned for performance, in addition to being vital for diagnosing memory problems.

Some Liberty-for-Java applications experienced performance degradation starting with Liberty-for-Java buildpack v3.37. This coincided with an updated IBM JRE included in the buildpack that enabled TransparentHugePage (THP) by default. In some multi-tenant environments, enabling THP causes performance degradation. This buildpack mitigates this problem by disabling THP. Users of buildpacks prior to v3.42 can disable THP by setting JVM arg -XX:-TransparentHugePage and restaging the application.  

This buildpack contains a fix for an unspecified vulnerability in Java SE related to the Java SE Libraries component (CVE-2020-2654)

Learn more:

• Liberty 20.0.0.4
• IBM JRE 8.0.6.7
• Adopt OpenJDK OpenJ9 11.06