RFR: 8314774: Optimize URLEncoder [v13]

[Glavo]

On Tue, 19 Sep 2023 11:16:11 GMT, Glavo <duke at openjdk.org> wrote:

>> I mainly made these optimizations:
>> 
>> * Avoid allocating `StringBuilder` when there are no characters in the URL that need to be encoded;
>> * ~Implement a fast path for UTF-8.~ (Has been removed from this PR)
>> 
>> In addition to improving performance, these optimizations also reduce temporary objects:
>> 
>> * It no longer allocates any object when there are no characters in the URL that need to be encoded;
>> * The initial size of StringBuilder is larger to avoid expansion as much as possible;
>> * ~For UTF-8, the temporary `CharArrayWriter`, strings and byte arrays are no longer needed.~ (Has been removed from this PR)
>> 
>> I also updated the tests to add more test cases.
>
> Glavo has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update src/java.base/share/classes/java/net/URLEncoder.java
>   
>   Co-authored-by: Claes Redestad <claes.redestad at oracle.com>

I ran tier1~2 tests and there were no new failures.

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PR Comment: https://git.openjdk.org/jdk/pull/15354#issuecomment-1725579151