static TableDescriptorModtime getTableDescriptorModtime(FileSystem fs, Path tableDir)
throws NullPointerException, IOException {
if (tableDir == null) throw new NullPointerException();
FileStatus status = getTableInfoPath(fs, tableDir);
if (status == null) {
throw new TableInfoMissingException("No .tableinfo file under "
+ tableDir.toUri());
}
int len = Ints.checkedCast(status.getLen());
byte [] content = new byte[len];
FSDataInputStream fsDataInputStream = fs.open(status.getPath());