RFR: 8273329: Remove redundant null check from String.getBytes(String charsetName)

[Roger Riggs]

On Fri, 3 Sep 2021 13:22:54 GMT, Сергей Цыпанов <github.com+10835776+stsypanov at openjdk.org> wrote:

> Current implementation looks like this:
> 
> public byte[] getBytes(String charsetName)
>         throws UnsupportedEncodingException {
>     if (charsetName == null) throw new NullPointerException();
>     return encode(lookupCharset(charsetName), coder(), value);
> }
> 
> Null check seems to be redundant here because the same check of `charsetName` is done within `String.lookupCharset(String)`:
> 
> private static Charset lookupCharset(String csn) throws UnsupportedEncodingException {
>     Objects.requireNonNull(csn);
>     try {
>         return Charset.forName(csn);
>     } catch (UnsupportedCharsetException | IllegalCharsetNameException x) {
>         throw new UnsupportedEncodingException(csn);
>     }
> }

Redundant null checks get collapsed by HotSpot, so not a performance improvement.
Having null checks at public entry points also shows a stack trace that is more specific about where the null came from. So not much value in changing this.

-------------

Marked as reviewed by rriggs (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/5361