code: public Map<String, MountInfo> getMountTable() {
      try (LockResource r = new LockResource(mReadLock)) {
        return new HashMap<>(mState.getMountTable());
      }
    }
docs: Returns a copy of the current mount table, the mount table is a map from Alluxio file system
  URIs to the corresponding mount point information.
  
  @return a copy of the current mount table