ADDITIONAL SYSTEM INFORMATION :
Reproducible at least on JDK11 and JDK15.

A DESCRIPTION OF THE PROBLEM :
Path.getFileName() throws StringIndexOutOfBoundsException when the path is a symlink to a network share.

I understand that the problem is in 'WindowsPathParser.parse()', which always appends trailing '\\' to '\\server\share', resulting in 'root' variable being longer than 'path'.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1) Create a symlink to amn existing network share with:
    mklink /d C:\temp\link \\localhost\share
2) Use test snippet

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Path.getFileName() shall return null
ACTUAL -
Path.getFileName() throws StringIndexOutOfBoundsException

---------- BEGIN SOURCE ----------
final Path path = Paths.get("C:/temp/link");
final Path realPath = path.toRealPath();
final Path fileName = realPath.getFileName();
---------- END SOURCE ----------

FREQUENCY : always