RFR: 8358533: Improve performance of java.io.Reader.readAllLines

[Shaojin Wen]

On Wed, 18 Jun 2025 00:04:37 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

> Replaces the implementation `readAllCharsAsString().lines().toList()` with reading into a temporary `char` array which is then processed to detect line terminators and copy non-terminating characters into strings which are added to the list.

src/java.base/share/classes/java/io/Reader.java line 492:

> 490:                     // Buffer content consumed so reload it.
> 491:                     if ((n = read(cb, 0, cb.length)) < 0) {
> 492:                         eos = eol = true;

Suggestion:

                        eos = true;

The local variable eol assignment here is not used and can be removed.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25863#discussion_r2153483905