@Override
  public boolean databaseExists(String database) {
    return metaStore.doAs(
        () -> {
          FileSystem fs = fs();
          return fs.exists(new Path(warehouse, database));
        });
  }
Hudi catalog implement in hadoop filesystem.
amoro-format-hudi/src/main/java/org/apache/amoro/formats/hudi/HudiHadoopCatalog.java