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8347763: [doc] Add documentation of module options for JEP 483

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Reviewed-by: iklam
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Calvin Cheung 2025-01-17 18:46:17 +00:00
parent 6cc1c0abdb
commit 17e3df652f
1 changed files with 34 additions and 5 deletions
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src/java.base/share/man/java.md
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@ -3969,11 +3969,40 @@ archive, you should make sure that the archive is created by at least version
- The CDS archive cannot be loaded if any JAR files in the class path or
module path are modified after the archive is generated.
- If any of the VM options `--upgrade-module-path`, `--patch-module` or
`--limit-modules` are specified, CDS is disabled. This means that the
JVM will execute without loading any CDS archives. In addition, if
you try to create a CDS archive with any of these 3 options specified,
the JVM will report an error.
### Module related options
The following module related options are supported by CDS: `--module-path`, `--module`,
`--add-modules`, and `--enable-native-access`.
The values for these options (if specified), should be identical when creating and using the
CDS archive. Otherwise, if there is a mismatch of any of these options, the CDS archive may be
partially or completely disabled, leading to lower performance.
- If the -XX:+AOTClassLoading options *was* used during CDS archive creation, the CDS archive
cannot be used, and the following error message is printed:
`CDS archive has aot-linked classes. It cannot be used when archived full module graph is not used`
- If the -XX:+AOTClassLoading options *was not* used during CDS archive creation, the CDS archive
can be used, but the "archived module graph" feature will be disabled. This can lead to increased
start-up time.
To diagnose problems with the above options, you can add `-Xlog:cds` to the application's VM
arguments. For example, if `--add-modules jdk.jconcole` was specified during archive creation
and `--add-modules jdk.incubator.vector` is specified during runtime, the following messages will
be logged:
`Mismatched values for property jdk.module.addmods`
`runtime jdk.incubator.vector dump time jdk.jconsole`
`subgraph jdk.internal.module.ArchivedBootLayer cannot be used because full module graph is disabled`
If any of the VM options `--upgrade-module-path`, `--patch-module` or
`--limit-modules` are specified, CDS is disabled. This means that the
JVM will execute without loading any CDS archives. In addition, if
you try to create a CDS archive with any of these 3 options specified,
the JVM will report an error.
## Performance Tuning Examples