private void logRefreshError(String what, String[] items, Throwable t) throws IOException {
    for (String item : items) {
      what += (item + ", ");
    }
    throw new IOException(what, t);
  }
This class localizes and manages jars for the functions allowed inside LLAP.
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/FunctionLocalizer.java