public void closeIfPossible() throws IOException {
    if (deprecated && activeQueriesCount.get() == 0) {
      close();
    }
  }
If this classloader is marked as deprecated, then this classloader can be closed after all
queries that use this classloader are completed.
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/udf/service/UDFClassLoader.java