public static String verifyPathnameExists(final String pathname) throws FileNotFoundException {
    if (isExistingPathname(pathname)) {
      return pathname;
    }

    throw new FileNotFoundException(String.format("Pathname (%1$s) could not be found!", pathname));
  }
Verifies that the specified pathname is valid and actually exists in the file system in
localhost. The pathname is considered valid if it is not null, empty or blank and exists in the
file system as a file path (which could represent a file or a directory).
<p>

@param pathname a String indicating the file path in the file system on localhost.
@return the pathname if valid and it exits.
@throws FileNotFoundException if the pathname is invalid or does not exist in the file system
        on localhost.
@see java.io.File#exists()
geode-core/src/main/java/org/apache/geode/internal/util/IOUtils.java