Integrated: 8316681: Rewrite URLEncoder.encode to use small reusable buffers

[Claes Redestad]

On Thu, 21 Sep 2023 14:32:46 GMT, Claes Redestad <redestad at openjdk.org> wrote:

> `URLEncoder` currently appends chars that needs encoding into a `java.io.CharArrayWriter`, converts that to a `String`, uses `String::getBytes` to get the encoded bytes and then appends these bytes in a escaped manner to the output stream. This is somewhat inefficient.
> 
> This PR replaces the `CharArrayWriter` with a reusable `CharBuffer` + `ByteBuffer` pair. This allows us to encode to the output `StringBuilder` in small chunks, with greatly reduced allocation as a result.
> 
> The exact size of the buffers is an open question, but generally it seems that a tiny buffer wins by virtue of allocating less, and that the per chunk overheads are relatively small.

This pull request has now been integrated.

Changeset: c24c66db
Author:    Claes Redestad <redestad at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/c24c66db97a52371875a63862f85ea5c2010d5a7
Stats:     96 lines in 4 files changed: 77 ins; 14 del; 5 mod

8316681: Rewrite URLEncoder.encode to use small reusable buffers

Reviewed-by: dfuchs, rriggs

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PR: https://git.openjdk.org/jdk/pull/15865