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

[Andrey Turbanov]

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.

test/micro/org/openjdk/bench/java/io/ReaderReadAllLines.java line 61:

> 59:     public List<String> readAllLines() throws IOException {
> 60:         List<String> lines;
> 61:         try (Reader reader = new CharArrayReader(chars);) {

Suggestion:

        try (Reader reader = new CharArrayReader(chars)) {

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PR Review Comment: https://git.openjdk.org/jdk/pull/25863#discussion_r2163248743