RFR: 8378698: Optimize Base64.Encoder#encodeToString

[Chen Liang]

On Thu, 26 Feb 2026 10:17:54 GMT, Eirik Bjørsnøs <eirbjo at openjdk.org> wrote:

>> Avoid a byte array copy in encodeToString by using JavaLangAccess#uncheckedNewStringWithLatin1Bytes
>
> src/java.base/share/classes/java/util/Base64.java line 351:
> 
>> 349:          */
>> 350:         public String encodeToString(byte[] src) {
>> 351:             byte[] encoded = encode(src);
> 
> Consider adding a comment here to make it clear that `encoded` is guaranteed to be ASCII-only.
> 
> Otherwise, using `uncheckedNewStringWithLatin1Bytes` would not be safe. Better to make this contract explicit with a comment.

`encoded` is already a well-behaved platform API, and this method already states:

> In other words, an invocation of this method has exactly the same effect as invoking `new String(encode(src), StandardCharsets.ISO_8859_1)`.

And this is exactly compatible with `uncheckedNewStringWithLatin1Bytes`.

Let's not add redundant comments.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29920#discussion_r2859802886