How to read .apn file in Matlab

I am trying to open .apn file (as text) of Physionet Apnea ECG dataset in matlab using rdann(-r a01, -a apn) but failed.

The erroe I faced is related "varargin" Please guide

[ann, anntype, subtype, chan, num, comments] = rdann('a01','apn');

Error is: Dot indexing is not supported for variables of this type.

Error in rdann (line 180)

data=dataJava.toArray();

Error in annot (line 19)

[ann, anntype, subtype, chan, num, comments] = rdann('a01.apn','apn');

[Walter Roberson]

The implementing code appears to be at https://archive.physionet.org/physiotools/matlab/wfdb-app-matlab/html/rdann.m

[Walter Roberson]

The code has

   dataJava=javaWfdbExec.execToStringList(wfdb_argument);
    data=dataJava.toArray();

but for whatever reason, dataJava is coming out as empty instead of as a Java array.