RFR: 8254876: (fs) NullPointerException not thrown when first argument to Path.of or Paths.get is null

[Brian Burkhalter]

On Mon, 2 Nov 2020 21:54:50 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> Please review this simple fix to have Path.of(String,String) throw a NullPointerException if the first parameter is null.
>
> src/java.base/unix/classes/sun/nio/fs/UnixFileSystem.java line 264:
> 
>> 262:             path = first;
>> 263:         } else {
>> 264:             if (first == null) {
> 
> `Objects.requireNonNull(first)` does this in fewer lines and a bit more explicitly.
> 
> Should it be checking `first` always, not just in the case `more.length != 0`?
> (It will throw NPE, but not until `UnixPath.normalizeAndCheck(path))`.

Good point on the Objects call. I checked the more.length == 0 case and let if fall through to the UnixPath method. It might be more straightforward to always check however.

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PR: https://git.openjdk.java.net/jdk/pull/1020