On Wed, 2 Mar 2022 20:28:45 GMT, Joe Darcy <da...@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. This is also only a partial solution, since the initial array is created and injected by the VM on a "root" Constructor/Method, see for example the code for new method: https://github.com/openjdk/jdk/blob/5c187e34a58769a129a0aae9e4937907c9060202/src/hotspot/share/runtime/reflection.cpp#L778 Depending on usage pattern most of the Constructor/Method objects created are such root objects (often created in bulk), and only those exposed to user code via a copy will benefit from this particular enhancement. Which might be a good optimization when getting the same Constructor/Method from the same class over and over. - Can we skip the `.clone()` when propagating these from a root object to one we'll expose? We have internal `getShared...` methods for that purpose. - If we update the JVM code to inject a reference to `Class.EMPTY_CLASS_ARRAY` and we can skip the `.clone()`ing as per above we should see a decent benefit overall. ------------- Changes requested by redestad (Reviewer). PR: https://git.openjdk.java.net/jdk/pull/7667
