On Mon, 13 Sep 2021 11:06:15 GMT, Сергей Цыпанов <github.com+10835776+stsypa...@openjdk.org> wrote:
> Currently the method is implemented like > > public List<Class<?>> parameterList() { > return Collections.unmodifiableList(Arrays.asList(ptypes.clone())); > } > > This seems to be excessive, as three objects are allocated here. Instead we > can use `List.of(ptypes)` which doesn't allocate anything for empty array and > for one of length 1 and 2 it allocates lightweight objects with 2 fields, > still copying longer arrays. This is likely to be fruitful as most of methods > have 0-2 parameters. > > Also there is a couple of cases when `MethodType.parameterLis()` is called to > get its size, which is excessive either as we can use > `MethodType.parameterCount()` instead. This change introduces a subtle behavior change in that `List.of` produce a `null`-hostile list, for example `list.contains(null)` will throw NPE. Does this need to be spelled out? (FTR I think such null-hostile behavior should be reconsidered) ------------- PR: https://git.openjdk.java.net/jdk/pull/5489