Our monthly update for IBM SDK, Java Technology Edition, Version 8 has arrived. This update includes some great new features, including a new garbage collection policy, improvements for applications that run inside containers, and shared classes support for nested jar files.

You can find the latest packages on our Downloads page.

To find out more about the highlights, read on …..

New Garbage Collection policy

The Eclipse OpenJ9 JVM has a new garbage collection policy that benefits short-lived applications that are not constrained by memory limits. When this policy is enabled, the Java object heap is expanded in the normal way until the limit is reached, but memory is not reclaimed through garbage collection, which avoids garbage collection pauses. You can set this option on the command line by specifying -Xgcpolicy:nogc.

Container awareness

The OpenJ9 JVM is now better at handling memory allocation in a container environment. If your application is running in a container and is not competing for memory with other applications, you can request a larger slice of memory to be allocated by setting the -XX:+UseContainerSupport option on the command line. If your container has more than 2 GB of memory available, 75% is allocated for the Java heap.

Another enhancement that works well for applications in containers is the ability to set the initial and maximum Java heap size as a percentage, rather than a fixed value. So if your application gets deployed in a different container that has less memory, it won’t acquire too much. This capability is added by implementing the following Oracle HotSpot options in the OpenJ9 VM:

  • -XX:MaxRAMPercentage
  • -XX:InitialRAMPercentage

Each option takes a percentage value between 0 and 100. For example, -XX:MaxRAMPercentage=60 requests 60% of the available memory limit in the container.

To find out more about the Eclipse OpenJ9 development plans for containers, read this article on the OpenJ9 blog.

Shared class support for nested JAR files

The com.ibm.oti.shared API is updated to support nested jar files.

More info

There’s a little more information about these updates in the Current news technote.

Our docs in the IBM Knowledge Center will be updated for publication at the end of July.

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