JDK-8350475 : Release Note: New System.map and System.dump_map Diagnostic Commands Have Been Added
  • Type: Sub-task
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: 22
  • Priority: P4
  • Status: Resolved
  • Resolution: Delivered
  • Submitted: 2025-02-21
  • Updated: 2025-02-28
  • Resolved: 2025-02-28
The Version table provides details related to the release that this issue/RFE will be addressed.

Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.

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JDK 21 JDK 22
21.0.8Unresolved 22Resolved
Description
New `System.map` and `System.dump_map` diagnostic commands have been added to jcmd. When executed, these commands print the virtual memory map of the JVM process, together with Native Memory Tracking information about the virtual memory segments. For the latter information to be displayed, Native Memory Tracking must be enabled.

`jcmd <pid> System.map` will print the virtual memory map of the JVM indicated by `<pid>` to the stdout of `jcmd`.

`jcmd <pid> System.dump_map` will cause the target JVM indicated by `<pid>` to print the virtual memory map to a file named `vm_memory_map_<pid>.txt` into the current directory of the target JVM.
Comments
Release note sub-tasks need to end in either "resolved :: delivered" or "closed :: withdrawn".
28-02-2025
RN looks good. I modified the title to confirm with RN guidelines. Has this RN been created for 22 so that a backport RN can be created for 21?
24-02-2025
[~dholmes] Thanks for looking at this. I added a description of the commands to run, as well as mentioning the two different command flavors.
21-02-2025
[~stuefe] as the Release Note is quite stand-alone perhaps an indication of how you run this diagnostic command would be useful; or a reference to the jcmd (?) tool.
21-02-2025