Creates a new directory or throws an exception if there is already a file or directory located by this path.
Note that the parent directory where this directory is going to be created must already exist. If you need to create all non-existent parent directories, use Path.createDirectories.
FileAlreadyExistsException - if there is already a file or directory located by this path
(optional specific exception, some implementations may throw more general IOException).
UnsupportedOperationException - if the attributesarray contains an attribute that cannot be set atomically
when creating the directory.