code: public void setWorkingDirectory(Path dir) {
      if (!dir.isAbsolute()) {
        FileSystem.LogForCollect
            .info("set job working directory to non absolute path: " + dir
                + " working directory: " + getWorkingDirectory());
      }
      dir = new Path(getWorkingDirectory(), dir);
      set("mapred.working.dir", dir.toString());
    }
docs: Set the current working directory for the default file system.
  
  @param dir the new current working directory.