RFR: 8294962: java.base jdk.internal.module package uses ASM to modify and write module-info.class

[Mandy Chung]

On Fri, 25 Nov 2022 14:38:55 GMT, Adam Sotona <asotona at openjdk.org> wrote:

> 8294962: java.base jdk.internal.module package uses ASM to modify and write module-info.class.
> This patch converts it to use Classfile API.
> 
> Please review.
> Thanks,
> Adam

src/java.base/share/classes/jdk/internal/module/ModuleInfoWriter.java line 37:

> 35: import jdk.internal.classfile.Classfile;
> 36: import jdk.internal.classfile.jdktypes.ModuleDesc;
> 37: import jdk.internal.classfile.jdktypes.PackageDesc;

I'm a bit surprised of `jdk.internal.classfile.jdktypes` package.   ClassFile API is JDK-specific.  Would `jdk.internal.classfile.constant` be more appropriate?

src/java.base/share/classes/jdk/internal/module/ModuleInfoWriter.java line 146:

> 144: 
> 145:                 // packages
> 146:                 md.packages().stream().map(PackageDesc::of).toList(),

When writing `module_info.class` via ASM, it only visits the packages if there are packages that aren't exported or open.

Does the ClassFile API add `ModulePackages` attribute only if there are packages that aren't exported or open?

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PR: https://git.openjdk.org/jdk/pull/11368