RFR: JDK-8177107: Reduce memory footprint of java.lang.reflect.Constructor/Method

[Claes Redestad]

On Wed, 2 Mar 2022 20:28:45 GMT, Joe Darcy <darcy at openjdk.org> wrote:

> Refactoring of Method and Constructor to share a single empty array for parameters and exceptions as well as type variables.
> 
> Existing core reflection regression tests pass with the change.

src/java.base/share/classes/java/lang/reflect/Executable.java line 59:

> 57: 
> 58:     @SuppressWarnings({"rawtypes"})
> 59:     static final TypeVariable[] NO_TYPE_VARS = new TypeVariable[0];

Since you asked me offline about some startup noise from this patch I took a look. This line might be another small contributor, since it means we're loading `jlr.TypeVariable` on JVM bootstrap. It would be nice if we could move this to `TypeVariable`, but we don't support private/package-private interface fields for some reason. Shouldn't we though, now that we have private interface fields, etc..?

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PR: https://git.openjdk.java.net/jdk/pull/7667