Without addBatch / executeBatch my program runs without problems:

[main] Start
[main] tickerSymbolExtern='monetdb'
[main] Start MonetDB
[main] database table COUNTRY           -        200 rows in total
[main] database table TIMEZONE          -         11 rows in total
[main] database table COUNTRY_STATE     -        500 rows so far
[main] database table COUNTRY_STATE     -        600 rows in total
[main] database table CITY              -        500 rows so far
[main] database table CITY              -       1000 rows so far
[main] database table CITY              -       1500 rows so far
[main] database table CITY              -       1800 rows in total
[main] database table COMPANY           -        500 rows so far
[main] database table COMPANY           -       1000 rows so far
[main] database table COMPANY           -       1500 rows so far
[main] database table COMPANY           -       2000 rows so far
[main] database table COMPANY           -       2500 rows so far
[main] database table COMPANY           -       3000 rows so far
[main] database table COMPANY           -       3500 rows so far
[main] database table COMPANY           -       4000 rows so far
[main] database table COMPANY           -       4500 rows so far
[main] database table COMPANY           -       5000 rows so far
[main] database table COMPANY           -       5400 rows in total
[main] duration in seconds:         52
[main] End   MonetDB
[main] End

With addBatch / executeBatch and a batch size of 1000 I get the following error:

[main] Start
[main] tickerSymbolExtern='monetdb'
[main] Start MonetDB
[main] database table COUNTRY           -        200 rows in total
[main] database table TIMEZONE          -         11 rows in total
[main] database table COUNTRY_STATE     -        500 rows so far
[main] database table COUNTRY_STATE     -        600 rows in total
[main] database table CITY              -        500 rows so far
[main] database table CITY              -       1000 rows so far
[main] database table CITY              -       1500 rows so far
java.sql.BatchUpdateException: Error(s) occurred while executing the batch, see next SQLExceptions for details
        at nl.cwi.monetdb.jdbc.MonetStatement.executeBatch(Unknown Source)
        at ch.konnexions.db_seeder.jdbc.AbstractJdbcSeeder.createDataInsert(AbstractJdbcSeeder.java:501)
        at ch.konnexions.db_seeder.jdbc.AbstractJdbcSeeder.createData(AbstractJdbcSeeder.java:404)
        at ch.konnexions.db_seeder.jdbc.AbstractJdbcSeeder.createData(AbstractJdbcSeeder.java:362)
        at ch.konnexions.db_seeder.DatabaseSeeder.main(DatabaseSeeder.java:141)
Processing of the script was aborted, error code=1

Both times the connection runs with autoCommit.