On Sun, 9 Apr 2023 02:28:37 GMT, Tingjun Yuan <d...@openjdk.org> wrote:
>> In the current implementation of `String.join(CharSequence, Iterable)`, the >> temp array `elems` is always initialized with a length of 8. It will cause >> many array recreations when the `Iterable` contains more than 8 elements. >> Furthermore, it's very common that an `Iterable` is also a `Collection`. So >> if the `Iterable` is an instance of `Collection`, the initial length of the >> array can be `((Collection<?>)elements).size()`. It will not change the >> current behavior even if the `Collection` is modified asynchronously. >> >> I don't know whether this change requires a CSR request. > > Tingjun Yuan has updated the pull request incrementally with one additional > commit since the last revision: > > Add benchmark Furthermore, I did not and will not defend against all possible errors. One possible solution is change the package-private `join` method to accept an `Iterable` rather an `Object[]`, and change `String.join(CharSequence, CharSequence...)` to wrap the array with `Arrays.asList(E...)`, then we don't have to create any copies. ------------- PR Comment: https://git.openjdk.org/jdk/pull/13383#issuecomment-1501408398
