public static boolean isAvroTableWithExternalSchema(Table table) {
    if (table.getSd().getSerdeInfo().getSerializationLib().equals(AVRO_SERDE_CLASSNAME)) {
      String schemaUrl = table.getParameters().get(AVRO_SCHEMA_URL_PROPERTY);
      if (schemaUrl != null && !schemaUrl.isEmpty()) {
        return true;
      }
    }
    return false;
  }
Checks if the table is valid based on the rules for strict managed tables.
@param conf
@param table
@return  Null if the table is valid, otherwise a string message indicating why the table is invalid.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/utils/HiveStrictManagedUtils.java