Glossary items by Sreekala-Gopakumar · Pull Request #1593 · eclipse-openj9/openj9-docs

Sreekala-Gopakumar · 2025-09-24T04:32:32Z

Part 1 - 07 Oct 2025

OpenJ9 Glossary terms

Co-authored by Copilot
Signed-off-by: Sreekala Gopakumar sreekala.gopakumar@ibm.com

Sreekala-Gopakumar · 2025-09-24T04:39:46Z

@pshipton - This is a trial for creation of a glossary for OpenJ9 by using AI. Could you please check whether the definitions are applicable to OpenJ9? If they are then I will continue adding glossary terms to this table in this same PR and submit them for your review.

After we have a reasonable number of glossary terms, we can merge these changes and make it available to the users in batches in different releases. I will use this PR for adding terms and submitting them for your review till we are ready to merge. I will create a new PR for the next batch after that.

Please let me know if this strategy is ok. Thanks!

pshipton · 2025-09-24T11:43:20Z

Looks reasonable to me. @amicic and @dmitripivkine should check the GC definitions.

We need the AI attribution.
https://github.com/eclipse-openj9/openj9/blob/master/CONTRIBUTING.md#generative-artificial-intelligence-usage-guidelines
// Some sections generated by <YOUR AI ASSISTANT>
and in the commit
Co-authored by <YOUR AI ASSISTANT>

Sreekala-Gopakumar · 2025-10-07T06:08:08Z

Jenkins doc stage

Sreekala-Gopakumar · 2025-10-07T08:54:08Z

Jenkins doc stage

Sreekala-Gopakumar · 2025-10-07T09:04:04Z

Jenkins doc stage

Sreekala-Gopakumar · 2025-10-07T09:10:07Z

@pshipton @amicic @dmitripivkine - Could you please check the definitions and let me know if the definitions are ok from OpenJ9 perspective. Thanks!

pshipton · 2025-10-09T17:56:12Z

+| **Class Data Sharing (CDS)** | VM feature that shares class metadata between VM instances to reduce startup time and memory usage. |
+| **Classpath (`-classpath`)** | Specifies the search path for application classes and resources. |
+| **Compressed References** | A memory optimization technique that stores object references in 32-bit format on 64-bit systems to reduce memory footprint. |
+| **Condition Exception Handling** | Refers to the mechanisms provided by OpenJ9 for managing exceptions and error conditions during Java application execution. These mechanisms include APIs and tools for diagnosing and responding to runtime issues. |


What is this definition for?

Not sure what you are asking. The definition is for Condition Exception Handling?

Yes, where is Condition Exception Handling referred to?

This is coming in the TOC only (under API Documentation -> Java 8 API). We can delete it from the Glossary if it is not required.

I don't think the definition is correct, we should either delete it or get it right. The only reference to "Condition Exception Handling" is the link, which is probably not correctly named. The actual documentation is for z/OS Language Environment condition handling.

Then it is better that it is deleted.

pshipton · 2025-10-09T17:56:57Z

+| **Classpath (`-classpath`)** | Specifies the search path for application classes and resources. |
+| **Compressed References** | A memory optimization technique that stores object references in 32-bit format on 64-bit systems to reduce memory footprint. |
+| **Condition Exception Handling** | Refers to the mechanisms provided by OpenJ9 for managing exceptions and error conditions during Java application execution. These mechanisms include APIs and tools for diagnosing and responding to runtime issues. |
+| **CRIU (Checkpoint/Restore In Userspace)** | Linux tool for checkpointing and restoring processes, which are used in OpenJ9. |


is used in OpenJ9? are -> is

"The processes, which are used in OpenJ9" not "the Linux tool which is used in....". I think it might be clearer if I change the sentence to "Linux tool for checkpointing and restoring processes that are used in OpenJ9."?

Linux tool for checkpointing and restoring processes that run using OpenJ9.

pshipton · 2025-10-09T18:42:18Z

Jenkins doc stage

pshipton · 2025-10-10T16:04:07Z

+*
+* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0 OR GPL-2.0-only WITH OpenJDK-assembly-exception-1.0
+-->
+<!--Some sections generated by Copilot -->


Pls specify Microsoft Copilot

Part 1 - 07 Oct 2025 OpenJ9 Glossary terms Co-authored by Microsoft Copilot Signed-off-by: Sreekala Gopakumar sreekala.gopakumar@ibm.com

Sreekala-Gopakumar · 2025-10-10T16:23:24Z

Jenkins doc stage

Sreekala-Gopakumar · 2026-01-07T05:09:41Z

Jenkins doc stage

Sreekala-Gopakumar · 2026-01-07T05:16:30Z

@pshipton - With the advent of IBM Bob, I have created a comprehensive glossary by using this tool. I have added 2 more columns - Category and Used in topics. From my perspective, the definitions are crisper and clearer. It is also an IBM tool so I assume that there won't be any legal confusions using this tool unlike the other tools I had used earlier.

Could you please check the technical accuracy of the definitions? If the content is ok we can make it available in the upcoming 0.57.0 release.

Thanks!

OpenJ9 Glossary terms Co-authored by IBM Bob Signed-off-by: Sreekala Gopakumar sreekala.gopakumar@ibm.com

Sreekala-Gopakumar · 2026-01-08T04:22:26Z

Jenkins doc stage

pshipton · 2026-01-19T18:12:29Z

~~The links are to the github repo and not the published user guide, some don't work, i.e. https://github.com/eclipse-openj9/openj9-docs/blob/master/docs/api-cuda.md~~ Ignore this, I wasn't looking at the staging site.

pshipton · 2026-01-19T17:46:22Z

+| Term | Definition | Category | Used In Topics |
+|------|------------|----------|----------------|
+| **Agent** | A component loaded into a VM to perform tasks like monitoring, profiling, or diagnostics | Diagnostics | [interface_jvmti.md](interface_jvmti.md) |
+| **AgentLoadException** | Exception thrown when an agent fails to load through the Attach API | Diagnostics | [attachapi.md](attachapi.md) |


Pls remove this one, it's a standard exception which is found in the javadoc.

pshipton · 2026-01-19T17:52:52Z

+| **AOT (Ahead-Of-Time) Compiler** | A compiler that dynamically compiles Java methods into native code at runtime and stores them in the [shared classes cache](shrc.md) for faster subsequent application starts. This compilation and storage improves startup performance for subsequent runs by avoiding interpretation. See [AOT Compiler](aot.md) | Compilation | [aot.md](aot.md), [shrc.md](shrc.md), [xaot.md](xaot.md), [xshareclasses.md](xshareclasses.md) |
+| **Application Throughput** | The amount of useful work an application completes per unit of time | Performance | [gc.md](gc.md), [jit.md](jit.md), [openj9_newuser.md](openj9_newuser.md) |
+| **Area-based Heap** | Divides the heap into nursery and tenure areas to optimize garbage collection based on object lifespan | GC | [gc.md](gc.md), [xgcpolicy.md](xgcpolicy.md) |
+| **Arraylet** | A representation technique for large arrays that cannot be contained in a single region, where arrays are split into smaller pieces (used in balanced GC policy before 0.53.0). Consists of a spine and leaves to help avoid contiguous memory allocation. See [Arraylets](allocation.md#arraylets) | Memory Management | [gc.md](gc.md), [allocation.md](allocation.md) |


They are still in use for the metronome policy.

Sreekala-Gopakumar · 2026-02-18T17:10:06Z

Closing this PR. Opened another PR for the latest Glossary topic. Refer to #1662

Sreekala-Gopakumar self-assigned this Sep 24, 2025

Sreekala-Gopakumar force-pushed the 2025Glossary branch from f89afeb to d9161ac Compare October 7, 2025 06:06

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Glossary items

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Part 1 - 07 Oct 2025 OpenJ9 Glossary terms Co-authored by Microsoft Copilot Signed-off-by: Sreekala Gopakumar sreekala.gopakumar@ibm.com

Sreekala-Gopakumar force-pushed the 2025Glossary branch from 28970f0 to 4b9df5f Compare October 10, 2025 16:22

OpenJ9 Glossary terms - IBM Bob

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OpenJ9 Glossary terms Co-authored by IBM Bob Signed-off-by: Sreekala Gopakumar sreekala.gopakumar@ibm.com

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